If you have recently run has issues with Microsoft Teams and run into error message 80080300 “We ran into a problem. Reconnecting…” this may be the reason why.

Microsoft is reporting that the most recent May 11, 2021 Windows 10 Cumulative Update KB5003169 (OS Build 18363.1556) is causing some issues for Windows 10 1909 users.

They report that after installing this update and restarting your device, you might be unable to sign in to some Microsoft 365 desktop client apps such as Microsoft Teams, OneDrive for Business and Microsoft Outlook. You might also receive an 80080300 error or “We ran into a problem. Reconnecting…” when attempting to authenticate or sign into Teams.

Solution to error 80080300 “We ran into a problem. Reconnecting…”

Fortunately, the solution is pretty simple. Microsoft recommends simply restarting your device. Most devices will sign into affected apps as expected for all subsequent restarts after the first restart that completes the installation of the update.

If this fails Microsoft recommends switching to the web or mobile versions of the app, as they are unaffected by the issue.

Microsoft is continuing to investigate the root cause of the problem.

via WindowsLatest