During authentication process (Jira Cloud and Confluence Cloud for Teams), users get 502 Bad Gateway nginx error message

Issue Summary

Multiple users reported an issue where they receive 502 Bad Gateway nginx error from auth.atlassian.net after putting in the email to authenticate. The issue is reproducible for Jira Cloud and Confluence Cloud users. For some users the issue does not exist if they are using MS Teams web version, however, for others the issue is reproducible on both desktop and web versions. 

Steps to Reproduce

1. Add Jira Cloud Tab to Microsoft Teams (step 1 and step 2 screenshots)
2. Enter Jira Cloud URL and click Connect button (step 3 screenshot)
3. Click Authorize in Jira (step 4 screenshot) 
4. Log in to Jira, enter email address and click Continue (step 5 screenshot)
5. 502 Bad Gateway nginx error received (502 bad gateway screenshot)

Expected Results

Users are successfully authenticate via both desktop and web versions of Microsoft Teams and can successfully use the integration.

Actual Results

Users cannot authenticate and receive 502 Bad Gateway error message. 

Workaround

Some users can successfully authenticate via MS Teams web version. 

If the issue exists in web version of the app too:

1. Ask the user to open an incognito mode browser tab and try the same steps as they would normally do.
2. In case the 502 error happens, ask the user to try to log in on their instance.
   • They should be disconnected with the following icon being shown in the top right:
   • 
3. Ask them to log in on their instance
4. If everything works correctly, ask them to repeat the integration process on MS Teams app