situation solved by installing client v1.6 beta.

just checked it - all allowed. and no changes was made in pc settings before error.
if i try to enter invalid acc login/pass - it returns "Username or password was wrong". so it means connection is alive, but it cant correctly interact to account entry at server db?
if i enter correct login/pass - it shows table with
"This app would like to:
Login via OpenID Connect
Permanent Login
View profile
Upload maps
Upload mods
Play in the game lobby
Deny - Authorize"
when i press authorize - throws back to welcome screen and few second later the same error table.

it returns error 2nd day. firstly i completely reinstalled faf from steam, and faf client. tried to change nick, pass, resync acc.
I was hoping that restarting the server last night would solve the problem, but nothing has changed.
java.util.concurrent.CompletionException: java.util.concurrent.CompletionException: com.faforever.client.login.LoginFailedException: Lost connection to server during login
at com.faforever.client.user.UserService.lambda$loginToLobbyServer$11(UserService.java:124)
at java.base/java.util.concurrent.CompletableFuture.uniHandle(CompletableFuture.java:930)
at java.base/java.util.concurrent.CompletableFuture$UniHandle.tryFire(CompletableFuture.java:907)
at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506)
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1769)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.util.concurrent.CompletionException: com.faforever.client.login.LoginFailedException: Lost connection to server during login
at org.springframework.aop.interceptor.AsyncExecutionAspectSupport.lambda$doSubmit$3(AsyncExecutionAspectSupport.java:279)
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1764)
... 3 more
Caused by: com.faforever.client.login.LoginFailedException: Lost connection to server during login
at com.faforever.client.remote.FafServerAccessorImpl$1.call(FafServerAccessorImpl.java:246)
at com.faforever.client.remote.FafServerAccessorImpl$1.call(FafServerAccessorImpl.java:213)
at javafx.concurrent.Task$TaskCallable.call(Task.java:1425)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at javafx.concurrent.Service.lambda$executeTask$6(Service.java:725)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
at javafx.concurrent.Service.lambda$executeTask$7(Service.java:724)
... 3 more

i've tried to completely reinstall downlords-faf-client, with selection english language, but same thing - at startup ir returns "error during login"

java.util.concurrent.CompletionException: java.util.concurrent.CompletionException: com.faforever.client.login.LoginFailedException: Lost connection to server during login
at com.faforever.client.user.UserService.lambda$loginToLobbyServer$11(UserService.java:124)
at java.base/java.util.concurrent.CompletableFuture.uniHandle(CompletableFuture.java:930)
at java.base/java.util.concurrent.CompletableFuture$UniHandle.tryFire(CompletableFuture.java:907)
at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506)
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1769)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.util.concurrent.CompletionException: com.faforever.client.login.LoginFailedException: Lost connection to server during login
at org.springframework.aop.interceptor.AsyncExecutionAspectSupport.lambda$doSubmit$3(AsyncExecutionAspectSupport.java:279)
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1764)
... 3 more
Caused by: com.faforever.client.login.LoginFailedException: Lost connection to server during login
at com.faforever.client.remote.FafServerAccessorImpl$1.call(FafServerAccessorImpl.java:246)
at com.faforever.client.remote.FafServerAccessorImpl$1.call(FafServerAccessorImpl.java:213)
at javafx.concurrent.Task$TaskCallable.call(Task.java:1425)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at javafx.concurrent.Service.lambda$executeTask$6(Service.java:725)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
at javafx.concurrent.Service.lambda$executeTask$7(Service.java:724)
... 3 more

today i played, but now:
java.lang.RuntimeException: Error during login
at com.faforever.client.login.LoginController.lambda$initialize$13(LoginController.java:207)
at com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:181)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:80)
at javafx.beans.property.ReadOnlyStringPropertyBase.fireValueChangedEvent(ReadOnlyStringPropertyBase.java:72)
at javafx.beans.property.ReadOnlyStringWrapper.fireValueChangedEvent(ReadOnlyStringWrapper.java:103)
at javafx.beans.property.StringPropertyBase.markInvalid(StringPropertyBase.java:111)
at javafx.beans.property.StringPropertyBase.set(StringPropertyBase.java:145)
at javafx.scene.web.WebEngine.updateLocation(WebEngine.java:434)
at javafx.scene.web.WebEngine$LoadWorker.dispatchLoadEvent(WebEngine.java:1364)
at javafx.scene.web.WebEngine$PageLoadListener.dispatchLoadEvent(WebEngine.java:1239)
at com.sun.webkit.WebPage.fireLoadEvent(WebPage.java:2524)
at com.sun.webkit.WebPage.fwkFireLoadEvent(WebPage.java:2369)
at com.sun.webkit.network.URLLoaderBase.twkWillSendRequest(Native Method)
at com.sun.webkit.network.HTTP2Loader.lambda$willSendRequest$14(HTTP2Loader.java:497)
at com.sun.webkit.network.HTTP2Loader.lambda$callBackIfNotCanceled$10(HTTP2Loader.java:437)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:428)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:427)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
at java.base/java.lang.Thread.run(Thread.java:832)