Microsoft Teams - we weren't able to connect. Sign in and we'll try again

Marvin Oco 

Marvin Oco Just reinstall the MS Teams app, and it fixes it.

in my case, I unconsciously register the Microsoft account of the one at work with my personal email, so it automatically sees 2 accounts as 1, which leads to the problem, so the advice is to register the Microsoft account at work with another email of yours and make sure two in the information of 2 Microsoft accounts are registered with 2 different email accounts, then delete the ms teams in the computer, re-download and use it normally.
in case there are still issues, just restart the computer launch it, it works for me.
hope you succeed

Marvin Oco Same issue started for me today as well.

I could find following logs:

info -- Fetching silent token with a web account
info -- Getting silent token.
info -- WAM: Silent token fetch complete.
info -- token fetch responded withs:5;e:80090030;
error -- (Account)ProviderError.s:5;e:80090030;
info -- sendReloginAuthResult with status 5

There is another thread about error 80090030:

https://answers.microsoft.com/en-us/windows/forum/all/error-code-80090030/cc5c7723-e6b5-4020-9828-284291f317fd

Interestingly, solution in this other thread seems to be rebooting the machine (like mentioned here). It might be linked to Trusted Platform Module or cached Office credentials - however, my credentials have not changed for some time.

Marvin Oco I'm seeing this issue too, with several colleagues reporting the same issue.  It seems to occur when PC has been idle for some time.  I tried the suggested reset method and clearing cache but no difference.  MS really needs to fix this.  It should warn users that it's not connnected or re-attempt to sign in.

Marvin Oco Do you see a status code anywhere on your screen? Looks something like this: 0xCAA20003. More status codes are documented here: https://support.microsoft.com/en-ie/office/why-am-i-having-trouble-signing-in-to-microsoft-teams-a02f683b-61a3-4008-9447-ee60c5593b0f.

Also, found an article explaining how to fix the issue: https://allthings.how/fix-microsoft-teams-error-we-werent-able-to-connect-sign-in-and-well-try-again/