Authorization error, what should I do?

Below are the error details

java.util.concurrent.CompletionException: org.springframework.web.reactive.function.client.WebClientRequestException: failed to resolve 'api.faforever.com' after 2 queries ; nested exception is java.net.UnknownHostException: failed to resolve 'api.faforever.com' after 2 queries
at java.base/java.util.concurrent.CompletableFuture.encodeRelay(CompletableFuture.java:367)
at java.base/java.util.concurrent.CompletableFuture.completeRelay(CompletableFuture.java:376)
at java.base/java.util.concurrent.CompletableFuture$UniRelay.tryFire(CompletableFuture.java:1093)
at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506)
at java.base/java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:2152)
at reactor.core.publisher.MonoToCompletableFuture.onError(MonoToCompletableFuture.java:76)
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221)
at reactor.core.publisher.Operators$MonoSubscriber.onError(Operators.java:1831)
at reactor.core.publisher.MonoCacheTime$CoordinatorSubscriber.signalCached(MonoCacheTime.java:331)
at reactor.core.publisher.MonoCacheTime$CoordinatorSubscriber.onError(MonoCacheTime.java:354)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onError(MonoFlatMap.java:172)
at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onError(Operators.java:2023)
at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onError(FluxOnAssembly.java:392)
at reactor.core.publisher.FluxMap$MapSubscriber.onError(FluxMap.java:132)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:106)
at reactor.core.publisher.Operators.error(Operators.java:196)
at reactor.core.publisher.MonoErrorSupplied.subscribe(MonoErrorSupplied.java:71)
at reactor.core.publisher.Mono.subscribe(Mono.java:3987)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:103)
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221)
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221)
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221)
at reactor.core.publisher.MonoNext$NextSubscriber.onError(MonoNext.java:93)
at reactor.core.publisher.MonoFlatMapMany$FlatMapManyMain.onError(MonoFlatMapMany.java:204)
at reactor.core.publisher.SerializedSubscriber.onError(SerializedSubscriber.java:124)
at reactor.core.publisher.FluxRetryWhen$RetryWhenMainSubscriber.whenError(FluxRetryWhen.java:224)
at reactor.core.publisher.FluxRetryWhen$RetryWhenOtherSubscriber.onError(FluxRetryWhen.java:273)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:413)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onNext(FluxConcatMap.java:250)
at reactor.core.publisher.EmitterProcessor.drain(EmitterProcessor.java:478)
at reactor.core.publisher.EmitterProcessor.tryEmitNext(EmitterProcessor.java:286)
at reactor.core.publisher.SinkManySerialized.tryEmitNext(SinkManySerialized.java:97)
at reactor.core.publisher.InternalManySink.emitNext(InternalManySink.java:27)
at reactor.core.publisher.FluxRetryWhen$RetryWhenMainSubscriber.onError(FluxRetryWhen.java:191)
at reactor.core.publisher.MonoCreate$DefaultMonoSink.error(MonoCreate.java:189)
at reactor.netty.http.client.HttpClientConnect$MonoHttpConnect$ClientTransportSubscriber.onError(HttpClientConnect.java:286)
at reactor.core.publisher.MonoCreate$DefaultMonoSink.error(MonoCreate.java:189)
at reactor.netty.resources.DefaultPooledConnectionProvider$DisposableAcquire.onError(DefaultPooledConnectionProvider.java:165)
at reactor.netty.internal.shaded.reactor.pool.AbstractPool$Borrower.fail(AbstractPool.java:427)
at reactor.netty.internal.shaded.reactor.pool.SimpleDequePool.lambda$drainLoop$5(SimpleDequePool.java:310)
at reactor.core.publisher.FluxDoOnEach$DoOnEachSubscriber.onError(FluxDoOnEach.java:186)
at reactor.core.publisher.MonoCreate$DefaultMonoSink.error(MonoCreate.java:189)
at reactor.netty.resources.DefaultPooledConnectionProvider$PooledConnectionAllocator$PooledConnectionInitializer.onError(DefaultPooledConnectionProvider.java:564)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.secondError(MonoFlatMap.java:192)
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onError(MonoFlatMap.java:259)
at reactor.netty.transport.TransportConnector$MonoChannelPromise.tryFailure(TransportConnector.java:464)
at reactor.netty.transport.TransportConnector.lambda$doResolveAndConnect$6(TransportConnector.java:271)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:578)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:552)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:491)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:616)
at io.netty.util.concurrent.DefaultPromise.setFailure0(DefaultPromise.java:609)
at io.netty.util.concurrent.DefaultPromise.setFailure(DefaultPromise.java:109)
at io.netty.resolver.InetSocketAddressResolver$1.operationComplete(InetSocketAddressResolver.java:62)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:578)
at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:571)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:550)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:491)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:616)
at io.netty.util.concurrent.DefaultPromise.setFailure0(DefaultPromise.java:609)
at io.netty.util.concurrent.DefaultPromise.tryFailure(DefaultPromise.java:117)
at io.netty.resolver.dns.DnsNameResolver.tryFailure(DnsNameResolver.java:936)
at io.netty.resolver.dns.DnsNameResolver.access$500(DnsNameResolver.java:90)
at io.netty.resolver.dns.DnsNameResolver$5.operationComplete(DnsNameResolver.java:956)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:578)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:552)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:491)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:616)
at io.netty.util.concurrent.DefaultPromise.setFailure0(DefaultPromise.java:609)
at io.netty.util.concurrent.DefaultPromise.tryFailure(DefaultPromise.java:117)
at io.netty.resolver.dns.DnsResolveContext.finishResolve(DnsResolveContext.java:1021)
at io.netty.resolver.dns.DnsResolveContext.tryToFinishResolve(DnsResolveContext.java:966)
at io.netty.resolver.dns.DnsResolveContext.query(DnsResolveContext.java:414)
at io.netty.resolver.dns.DnsResolveContext.onResponse(DnsResolveContext.java:601)
at io.netty.resolver.dns.DnsResolveContext.access$400(DnsResolveContext.java:63)
at io.netty.resolver.dns.DnsResolveContext$2.operationComplete(DnsResolveContext.java:458)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:578)
at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:571)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:550)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:491)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:616)
at io.netty.util.concurrent.DefaultPromise.setSuccess0(DefaultPromise.java:605)
at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:104)
at io.netty.resolver.dns.DnsQueryContext.trySuccess(DnsQueryContext.java:201)
at io.netty.resolver.dns.DnsQueryContext.finish(DnsQueryContext.java:193)
at io.netty.resolver.dns.DnsNameResolver$DnsResponseHandler.channelRead(DnsNameResolver.java:1230)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.netty.channel.nio.AbstractNioMessageChannel$NioMessageUnsafe.read(AbstractNioMessageChannel.java:93)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:719)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:655)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:581)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: org.springframework.web.reactive.function.client.WebClientRequestException: failed to resolve 'api.faforever.com' after 2 queries ; nested exception is java.net.UnknownHostException: failed to resolve 'api.faforever.com' after 2 queries
at org.springframework.web.reactive.function.client.ExchangeFunctions$DefaultExchangeFunction.lambda$wrapException$9(ExchangeFunctions.java:137)
Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException:
Error has been observed at the following site(s):
|_ checkpoint ⇢ Request to GET https://api.faforever.com/me [DefaultWebClient]
Stack trace:
at org.springframework.web.reactive.function.client.ExchangeFunctions$DefaultExchangeFunction.lambda$wrapException$9(ExchangeFunctions.java:137)
at reactor.core.publisher.MonoErrorSupplied.subscribe(MonoErrorSupplied.java:70)
at reactor.core.publisher.Mono.subscribe(Mono.java:3987)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:103)
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221)
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221)
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221)
at reactor.core.publisher.MonoNext$NextSubscriber.onError(MonoNext.java:93)
at reactor.core.publisher.MonoFlatMapMany$FlatMapManyMain.onError(MonoFlatMapMany.java:204)
at reactor.core.publisher.SerializedSubscriber.onError(SerializedSubscriber.java:124)
at reactor.core.publisher.FluxRetryWhen$RetryWhenMainSubscriber.whenError(FluxRetryWhen.java:224)
at reactor.core.publisher.FluxRetryWhen$RetryWhenOtherSubscriber.onError(FluxRetryWhen.java:273)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:413)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onNext(FluxConcatMap.java:250)
at reactor.core.publisher.EmitterProcessor.drain(EmitterProcessor.java:478)
at reactor.core.publisher.EmitterProcessor.tryEmitNext(EmitterProcessor.java:286)
at reactor.core.publisher.SinkManySerialized.tryEmitNext(SinkManySerialized.java:97)
at reactor.core.publisher.InternalManySink.emitNext(InternalManySink.java:27)
at reactor.core.publisher.FluxRetryWhen$RetryWhenMainSubscriber.onError(FluxRetryWhen.java:191)
at reactor.core.publisher.MonoCreate$DefaultMonoSink.error(MonoCreate.java:189)
at reactor.netty.http.client.HttpClientConnect$MonoHttpConnect$ClientTransportSubscriber.onError(HttpClientConnect.java:286)
at reactor.core.publisher.MonoCreate$DefaultMonoSink.error(MonoCreate.java:189)
at reactor.netty.resources.DefaultPooledConnectionProvider$DisposableAcquire.onError(DefaultPooledConnectionProvider.java:165)
at reactor.netty.internal.shaded.reactor.pool.AbstractPool$Borrower.fail(AbstractPool.java:427)
at reactor.netty.internal.shaded.reactor.pool.SimpleDequePool.lambda$drainLoop$5(SimpleDequePool.java:310)
at reactor.core.publisher.FluxDoOnEach$DoOnEachSubscriber.onError(FluxDoOnEach.java:186)
at reactor.core.publisher.MonoCreate$DefaultMonoSink.error(MonoCreate.java:189)
at reactor.netty.resources.DefaultPooledConnectionProvider$PooledConnectionAllocator$PooledConnectionInitializer.onError(DefaultPooledConnectionProvider.java:564)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.secondError(MonoFlatMap.java:192)
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onError(MonoFlatMap.java:259)
at reactor.netty.transport.TransportConnector$MonoChannelPromise.tryFailure(TransportConnector.java:464)
at reactor.netty.transport.TransportConnector.lambda$doResolveAndConnect$6(TransportConnector.java:271)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:578)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:552)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:491)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:616)
at io.netty.util.concurrent.DefaultPromise.setFailure0(DefaultPromise.java:609)
at io.netty.util.concurrent.DefaultPromise.setFailure(DefaultPromise.java:109)
at io.netty.resolver.InetSocketAddressResolver$1.operationComplete(InetSocketAddressResolver.java:62)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:578)
at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:571)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:550)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:491)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:616)
at io.netty.util.concurrent.DefaultPromise.setFailure0(DefaultPromise.java:609)
at io.netty.util.concurrent.DefaultPromise.tryFailure(DefaultPromise.java:117)
at io.netty.resolver.dns.DnsNameResolver.tryFailure(DnsNameResolver.java:936)
at io.netty.resolver.dns.DnsNameResolver.access$500(DnsNameResolver.java:90)
at io.netty.resolver.dns.DnsNameResolver$5.operationComplete(DnsNameResolver.java:956)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:578)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:552)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:491)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:616)
at io.netty.util.concurrent.DefaultPromise.setFailure0(DefaultPromise.java:609)
at io.netty.util.concurrent.DefaultPromise.tryFailure(DefaultPromise.java:117)
at io.netty.resolver.dns.DnsResolveContext.finishResolve(DnsResolveContext.java:1021)
at io.netty.resolver.dns.DnsResolveContext.tryToFinishResolve(DnsResolveContext.java:966)
at io.netty.resolver.dns.DnsResolveContext.query(DnsResolveContext.java:414)
at io.netty.resolver.dns.DnsResolveContext.onResponse(DnsResolveContext.java:601)
at io.netty.resolver.dns.DnsResolveContext.access$400(DnsResolveContext.java:63)
at io.netty.resolver.dns.DnsResolveContext$2.operationComplete(DnsResolveContext.java:458)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:578)
at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:571)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:550)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:491)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:616)
at io.netty.util.concurrent.DefaultPromise.setSuccess0(DefaultPromise.java:605)
at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:104)
at io.netty.resolver.dns.DnsQueryContext.trySuccess(DnsQueryContext.java:201)
at io.netty.resolver.dns.DnsQueryContext.finish(DnsQueryContext.java:193)
at io.netty.resolver.dns.DnsNameResolver$DnsResponseHandler.channelRead(DnsNameResolver.java:1230)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.netty.channel.nio.AbstractNioMessageChannel$NioMessageUnsafe.read(AbstractNioMessageChannel.java:93)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:719)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:655)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:581)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.net.UnknownHostException: failed to resolve 'api.faforever.com' after 2 queries
at io.netty.resolver.dns.DnsResolveContext.finishResolve(DnsResolveContext.java:1013)
at io.netty.resolver.dns.DnsResolveContext.tryToFinishResolve(DnsResolveContext.java:966)
at io.netty.resolver.dns.DnsResolveContext.query(DnsResolveContext.java:414)
at io.netty.resolver.dns.DnsResolveContext.onResponse(DnsResolveContext.java:601)
at io.netty.resolver.dns.DnsResolveContext.access$400(DnsResolveContext.java:63)
at io.netty.resolver.dns.DnsResolveContext$2.operationComplete(DnsResolveContext.java:458)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:578)
at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:571)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:550)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:491)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:616)
at io.netty.util.concurrent.DefaultPromise.setSuccess0(DefaultPromise.java:605)
at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:104)
at io.netty.resolver.dns.DnsQueryContext.trySuccess(DnsQueryContext.java:201)
at io.netty.resolver.dns.DnsQueryContext.finish(DnsQueryContext.java:193)
at io.netty.resolver.dns.DnsNameResolver$DnsResponseHandler.channelRead(DnsNameResolver.java:1230)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.netty.channel.nio.AbstractNioMessageChannel$NioMessageUnsafe.read(AbstractNioMessageChannel.java:93)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:719)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:655)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:581)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.base/java.lang.Thread.run(Thread.java:832)

This is a known issue with client 1.6.0 and some users dns configuration. You can try using the beta client for the next version found here https://github.com/FAForever/downlords-faf-client/releases/tag/v2021.10.0-beta1

User have reported it resolves the issue.