Gmail hacked?

At the next request to Gmail, I was asked to accept an outdated certificate. "Slavik ochkanul", but accepted. Now, after a request after a long redirection flies

Google Error
Bad request
Your client has issued a malformed or illegal request.

At the same time, Gmail notifier is working properly.
What to do?

UPD: The Google Documentation and Google Calendar also fell off. Guglorider and google pictures work.
')
UPD2: Removed through a snap certificate:

Thawte SGC CA
Thawte Consulting (Pty) Ltd.
ZA

Returned to the beginning. Has anyone else asked Google to accept this certificate?

UPD3: After restarting the browser, everything was back to normal. The causes of the phenomenon remain a mystery ...