Jacques,

Are the IDEA proxy settings correct (user/password)? I mean is it used OK in other IDEA communications?

Anyway, we need to report the error cause in a more user-friendly way.

Yes they are. With them I can I can download plugins, schemas...
I just has to stop using proxies to connect to the TC server.
I did not upgrade IDEA, only TC. I also did not change my proxy settings so it is pointing at a change in the TC IDEA plugin.
Maybe an incompatible changes between the plugin and IDEA? I am using IDEA 7693

What type of proxy authentication do you use? NTLM or HTTP basic authentication?

We added a checkbox to plugin login dialog indicating whether IDEA proxy settings should be used or not, we also added support for Basic proxy authentication. There is also rudimentary support for NTLM proxy authentication. However NTLM proxy authentication requires username in IDEA proxy settings to be specified in the form: <domainname>\<username>.

I've attached a new version of IDEA plugin with this checkbox. Could you please check whether it works for you? It will be good to know whether proxy authentication support works for you too. Please use full hostname in the plugin login dialog if you are using proxy settings.

The attached plugin works when I disable the proxy.
However I cannot connect to TC server if I have the proxy turned on.
I am not sure how to determine whether it would be NTLM. We connect to our proxy through port 80 so I would think it is HTTP.
I did not know IDEA proxy settings could apply to NTLM.

Thanks for the quick response as usual!

Have you tried to specify username in proxy settings in the form <domainname>\<username> ?

I guess we have just an http proxy.
I get this exception when I do Domain\Username in the 'login' field of the proxy settings

ntlm authorization challenge expected, but not found: ntlm authorization challenge expected, but not found
org.apache.commons.httpclient.auth.AuthenticationException: ntlm authorization challenge expected, but not found
	at org.apache.commons.httpclient.auth.AuthChallengeProcessor.processChallenge(AuthChallengeProcessor.java:158)
	at org.apache.commons.httpclient.HttpMethodDirector.processProxyAuthChallenge(HttpMethodDirector.java:753)
	at org.apache.commons.httpclient.HttpMethodDirector.processAuthenticationResponse(HttpMethodDirector.java:665)
	at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:192)
	at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:396)
	at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:324)
	at jetbrains.buildServer.xmlrpc.impl.MyXmlRpcTransport.sendXmlRpc(MyXmlRpcTransport.java:50)
	at org.apache.xmlrpc.XmlRpcClientWorker.execute(XmlRpcClientWorker.java:72)
	at org.apache.xmlrpc.TCXmlRpcClient$1.execute(TCXmlRpcClient.java:65)
	at org.apache.xmlrpc.XmlRpcClient.execute(XmlRpcClient.java:194)
	at org.apache.xmlrpc.XmlRpcClient.execute(XmlRpcClient.java:185)
	at org.apache.xmlrpc.XmlRpcClient.execute(XmlRpcClient.java:178)
	at jetbrains.buildServer.xmlrpc.impl.CommonsXmlRpcTargetImpl$1.execute(CommonsXmlRpcTargetImpl.java:53)
	at jetbrains.buildServer.xmlrpc.AbstractXmlRpcTarget.call(AbstractXmlRpcTarget.java:53)
	at jetbrains.buildServer.xmlrpc.AbstractXmlRpcTarget.call(AbstractXmlRpcTarget.java:30)
	at jetbrains.buildServer.serverProxy.ClientXmlRpcExecutorFacade.callXmlRpcInt(ClientXmlRpcExecutorFacade.java:37)
	at jetbrains.buildServer.serverProxy.ClientXmlRpcExecutorFacade.callXmlRpc(ClientXmlRpcExecutorFacade.java:26)
	at jetbrains.buildServer.serverProxy.RemoteBuildServerFacade.checkServerVersion(RemoteBuildServerFacade.java:907)
	at jetbrains.buildServer.serverProxy.RemoteBuildServerFacade.checkPassword(RemoteBuildServerFacade.java:587)
	at jetbrains.buildServer.TeamCitySnapshot$7.run(TeamCitySnapshot.java:391)
	at jetbrains.buildServer.TeamCityProcessManager.performAction(TeamCityProcessManager.java:83)
	at jetbrains.buildServer.TeamCitySnapshot.authorize(TeamCitySnapshot.java:379)
	at jetbrains.buildServer.BuildserverLoginPanel.login(BuildserverLoginPanel.java:166)
	at jetbrains.buildServer.login.BuildServerLoginDialog$1.run(BuildServerLoginDialog.java:57)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
	at java.lang.Thread.run(Thread.java:619)

Thank you Jacques for your time. We decided to close this bug as resolved. It seems that support of other proxy authentication types (like NTLM) is out of scope of this bug, and we are not very interested to implement it now since there are workarounds and there are no requests for this feature. Will probably return to this issue later if users start experience problems that cannot be workarounded.