Teams has been down for dozens of our users today and I cannot find anything pointing to why. Been on the platform for months and today complaints started that people were getting "failed to send" on every message & trying via web just posted "we can't access your content". I have not found any solution to this and there is no logging to help diagnose anything. Singing out and back in, restarting apps/computers, nothing brings them back to sending messages.
Looks like there was an issue with an update earlier that caused sign in issues. And it probabaly was causing the other issues as well. Says it’s been fixed thou so not sure if you are still having the issue.