java.util.concurrent.TimeoutException

Have you tried with a VPN from a different country?
Also try to disable any security software, firewall, etc. that can interfere with network. Just to test it.

Same issue here. After reinstalling everything (SupComFA, FAF client, Java, etc.) the issue still occurs. After disabling the firewall and allowing faf-client.exe through the firewall, it still doesn't work.

Change default web browser to something. Client cant detect that you logged in from browser

any fix for this, i now have this issue after changing internet provider.

I have this same issue. I've tried reinstalling, turning firewall off, making rules to allow inbound/outbound connections, changed my default browser several times between firefox/opera/operagx. Nothing seems to work.

its just a never ending logging in screen, watching that little circle going round and round.

Recently updated to the 2023.2.0.
My main home desktop PC took the update just fine.
My laptop did not. I get:

Client Version: 2023.2.0
java.util.concurrent.TimeoutException: Did not observe any item or terminal signal within 60000ms in 'sinkOneMulticast' (and no fallback has been configured)
	at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.handleTimeout(FluxTimeout.java:295)
	at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.doTimeout(FluxTimeout.java:280)
	at reactor.core.publisher.FluxTimeout$TimeoutTimeoutSubscriber.onNext(FluxTimeout.java:419)
	at reactor.core.publisher.FluxOnErrorReturn$ReturnSubscriber.onNext(FluxOnErrorReturn.java:162)
	at reactor.core.publisher.MonoDelay$MonoDelayRunnable.propagateDelay(MonoDelay.java:271)
	at reactor.core.publisher.MonoDelay$MonoDelayRunnable.run(MonoDelay.java:286)
	at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:68)
	at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:28)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:833)

I have tried Microsoft Edge, Firefox and Brave browsers. The outcome is always the same.

For what its worth, VPN worked as a workaround, but the issue seems to have gone after the latest 23.3.0 patch.

i have the same problem i litterly tried every thing still cant figure it out