I have some very strange problem with connecting to AWS Cloud Console on my Ubuntu 18.04 host. When I open https://aws.amazon.com/console/, I can click on the "Sign in" button at top right, the URL redirects to https://console.aws.amazon.com/console/home, a loading spinner appears, but then URL changes to https://eu-west-1.console.aws.amazon.com/console/home?region=eu-west-1 and the browser shows connection error.
In one case the error (on Firefox) is "Secure Connection Failed. An error occurred during a connection to eu-west-1.console.aws.amazon.com. PR_END_OF_FILE_ERROR". But then for a subsequent unsuccessful attempts sometimes the error is "The connection has timed out. An error occurred during a connection to eu-west-1.console.aws.amazon.com. PR_IO_TIMEOUT_ERROR"
The problem is weirdly universal: the failure is in Firefox, Chrome, and even in Chrome in Windows VM, and Firefox in Linux VM on this Ubuntu host. Doesn't matter if I clear cache and cookies, or use private/incognito mode. If I try to access the AWS Console from another computer in my network, there are no problems (tested on Windows 10 and Ubuntu 19.10). I have no problems connecting also from this computer, when I boot it in Windows 10 (dual boot). So I figure that is something to do with how the Ubuntu 18.04 host processes some specific SSL network traffic.
My system time is up to date, synced with time server. I haven't encountered problems with any other https hosts. The console opened just fine about 4 days ago, so this is a pretty recent behaviour.
Update: If I go ahead and manually change the failing URL from https://eu-west-1.console.aws.amazon.com/console/home?region=eu-west-1 to https://eu-west-2.console.aws.amazon.com/console/home?region=eu-west-2, then the console opens, but at London region. If I then try to switch to Europe (Ireland) eu-west-1 region from the region dropdown at top right, I get the "The connection has timed out" error, as previously. The sad thing is that my EC2 instances are in eu-west-1 region, where I have trouble connecting to. I wish this was the problem at AWS, but it most certainly is not.