Something went wrong while attempting to validate your credentials.

[sutibun]

Trying to use the website plugin in (new)teams, when loading the site it tries to authenticate by having me log in then fails with the following error: Something went wrong while attempting to validate your credentials. The cloud plug in works fine just having issues with the website plug in. This still works in Classic teams without issue. I have reverted for now but will need this working in the coming months when Microsoft changes permanently to new teams. 

[Paul Fearn]

This also impacts my customer since they moved to the new MS Teams due to Classic Teams now being unsupported.

Until there is a fix for this, MS Teams website tabs which works with many other applications will not work with Atlassian Jira or Confluence (and I suspect any other Atlassian products). 

[Tim Herremans]

This also impacts my company's use of Teams. The project manager can no longer log into Jira within Teams via the Website link at the top of the Teams group page. I had to manually revert her back to Classic Teams so that this function works.

What is the cause?