Myself and another person have both tried this with the same result. This is the fist time our company has tried to integrate MS Teams with Jira Cloud.
When I add the "Jira Cloud" integration in MS Teams, I get to a screen where I authenticate with Office365 which works, I am then presented with this screen:

Once I press on that, I am then asked to log in with my Atlassian account which has access to Jira Cloud, and I am presented with this screen:

I then tried the same thing through the Web Client for Teams and got the same result. I got someone with admin permissions in Jira to also try and they get the same result.
Does anyone have an idea of why this might be happening? Also if I need to log a support ticket, would I do that with Microsoft or Atlassian?
Cheers!