I got error every time when I try to enter the game or create own game

java.util.concurrent.CompletionException: error="access_denied", error_description="Error requesting access token."
at org.springframework.aop.interceptor.AsyncExecutionAspectSupport.lambda$doSubmit$3(AsyncExecutionAspectSupport.java:279)
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1764)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: error="access_denied", error_description="Error requesting access token."
at org.springframework.security.oauth2.client.token.OAuth2AccessTokenSupport.retrieveToken(OAuth2AccessTokenSupport.java:149)
at org.springframework.security.oauth2.client.token.grant.password.ResourceOwnerPasswordAccessTokenProvider.obtainAccessToken(ResourceOwnerPasswordAccessTokenProvider.java:52)
at org.springframework.security.oauth2.client.token.AccessTokenProviderChain.obtainNewAccessTokenInternal(AccessTokenProviderChain.java:152)
at org.springframework.security.oauth2.client.token.AccessTokenProviderChain.obtainAccessToken(AccessTokenProviderChain.java:125)
at org.springframework.security.oauth2.client.OAuth2RestTemplate.acquireAccessToken(OAuth2RestTemplate.java:225)
at org.springframework.security.oauth2.client.OAuth2RestTemplate.getAccessToken(OAuth2RestTemplate.java:177)
at org.springframework.security.oauth2.client.OAuth2RestTemplate.createRequest(OAuth2RestTemplate.java:109)
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:771)
at org.springframework.security.oauth2.client.OAuth2RestTemplate.doExecute(OAuth2RestTemplate.java:132)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:710)
at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:333)
at com.faforever.client.api.FafApiAccessorImpl.getPage(FafApiAccessorImpl.java:752)
at com.faforever.client.api.FafApiAccessorImpl.getPage(FafApiAccessorImpl.java:721)
at com.faforever.client.api.FafApiAccessorImpl.getMany(FafApiAccessorImpl.java:711)
at com.faforever.client.api.FafApiAccessorImpl.getFeaturedMods(FafApiAccessorImpl.java:204)
at jdk.internal.reflect.GeneratedMethodAccessor103.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:344)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:198)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
at org.springframework.cache.interceptor.CacheInterceptor.lambda$invoke$0(CacheInterceptor.java:54)
at org.springframework.cache.interceptor.CacheAspectSupport.invokeOperation(CacheAspectSupport.java:366)
at org.springframework.cache.interceptor.CacheAspectSupport.lambda$handleSynchronizedGet$1(CacheAspectSupport.java:447)
at org.springframework.cache.caffeine.CaffeineCache$LoadFunction.apply(CaffeineCache.java:168)
at com.github.benmanes.caffeine.cache.UnboundedLocalCache.lambda$computeIfAbsent$2(UnboundedLocalCache.java:238)
at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1708)
at com.github.benmanes.caffeine.cache.UnboundedLocalCache.computeIfAbsent(UnboundedLocalCache.java:234)
at com.github.benmanes.caffeine.cache.LocalCache.computeIfAbsent(LocalCache.java:108)
at com.github.benmanes.caffeine.cache.LocalManualCache.get(LocalManualCache.java:62)
at org.springframework.cache.caffeine.CaffeineCache.get(CaffeineCache.java:90)
at org.springframework.cache.interceptor.CacheAspectSupport.handleSynchronizedGet(CacheAspectSupport.java:442)
at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:382)
at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:345)
at org.springframework.cache.interceptor.CacheInterceptor.invoke(CacheInterceptor.java:64)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215)
at com.sun.proxy.$Proxy80.getFeaturedMods(Unknown Source)
at com.faforever.client.remote.FafService.getFeaturedMods(FafService.java:281)
at com.faforever.client.remote.FafService$$FastClassBySpringCGLIB$$6c91c77e.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
at org.springframework.aop.interceptor.AsyncExecutionInterceptor.lambda$invoke$0(AsyncExecutionInterceptor.java:115)
at org.springframework.aop.interceptor.AsyncExecutionAspectSupport.lambda$doSubmit$3(AsyncExecutionAspectSupport.java:276)
... 4 more
Caused by: org.springframework.web.client.ResourceAccessException: I/O error on POST request for "https://api.faforever.com/oauth/token": PKIX path validation failed: java.security.cert.CertPathValidatorException: validity check failed; nested exception is javax.net.ssl.SSLHandshakeException: PKIX path validation failed: java.security.cert.CertPathValidatorException: validity check failed
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:784)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:731)
at org.springframework.security.oauth2.client.token.OAuth2AccessTokenSupport.retrieveToken(OAuth2AccessTokenSupport.java:141)
... 49 more
Caused by: javax.net.ssl.SSLHandshakeException: PKIX path validation failed: java.security.cert.CertPathValidatorException: validity check failed
at java.base/sun.security.ssl.Alert.createSSLException(Alert.java:131)
at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:369)
at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:312)
at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:307)
at java.base/sun.security.ssl.CertificateMessage$T13CertificateConsumer.checkServerCerts(CertificateMessage.java:1357)
at java.base/sun.security.ssl.CertificateMessage$T13CertificateConsumer.onConsumeCertificate(CertificateMessage.java:1232)
at java.base/sun.security.ssl.CertificateMessage$T13CertificateConsumer.consume(CertificateMessage.java:1175)
at java.base/sun.security.ssl.SSLHandshake.consume(SSLHandshake.java:396)
at java.base/sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:480)
at java.base/sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:458)
at java.base/sun.security.ssl.TransportContext.dispatch(TransportContext.java:199)
at java.base/sun.security.ssl.SSLTransport.decode(SSLTransport.java:171)
at java.base/sun.security.ssl.SSLSocketImpl.decode(SSLSocketImpl.java:1488)
at java.base/sun.security.ssl.SSLSocketImpl.readHandshakeRecord(SSLSocketImpl.java:1394)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:441)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:412)
at java.base/sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:567)
at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:183)
at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:142)
at org.springframework.http.client.SimpleBufferingClientHttpRequest.executeInternal(SimpleBufferingClientHttpRequest.java:76)
at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48)
at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:66)
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:775)
... 51 more
Caused by: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: validity check failed
at java.base/sun.security.validator.PKIXValidator.doValidate(PKIXValidator.java:369)
at java.base/sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:275)
at java.base/sun.security.validator.Validator.validate(Validator.java:264)
at java.base/sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:231)
at java.base/sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:132)
at java.base/sun.security.ssl.CertificateMessage$T13CertificateConsumer.checkServerCerts(CertificateMessage.java:1341)
... 69 more
Caused by: java.security.cert.CertPathValidatorException: validity check failed
at java.base/sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(PKIXMasterCertPathValidator.java:135)
at java.base/sun.security.provider.certpath.PKIXCertPathValidator.validate(PKIXCertPathValidator.java:237)
at java.base/sun.security.provider.certpath.PKIXCertPathValidator.validate(PKIXCertPathValidator.java:145)
at java.base/sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(PKIXCertPathValidator.java:84)
at java.base/java.security.cert.CertPathValidator.validate(CertPathValidator.java:309)
at java.base/sun.security.validator.PKIXValidator.doValidate(PKIXValidator.java:364)
... 74 more
Caused by: java.security.cert.CertificateNotYetValidException: NotBefore: Mon Mar 01 22:17:37 EET 2021
at java.base/sun.security.x509.CertificateValidity.valid(CertificateValidity.java:273)
at java.base/sun.security.x509.X509CertImpl.checkValidity(X509CertImpl.java:665)
at java.base/sun.security.provider.certpath.BasicChecker.verifyValidity(BasicChecker.java:190)
at java.base/sun.security.provider.certpath.BasicChecker.check(BasicChecker.java:144)
at java.base/sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(PKIXMasterCertPathValidator.java:125)
... 79 more

Our Let's encrypt certificate gets renewed every 30 days (that's how Let's encrypt works). Either you exactly hit the time when the old certificate was replaced or you have a tiny issue that the time it starts to be valid from is not correctly compared to your timezones time.
Nevertheless. Please retry (close and reopen the client) in an hour, in 2 hours, in a day. This should fix itself.

Thanks
Will wait

Issue resolved
You are right I had troubles with timezone