A rare issue with the uninstall of classic Teams has been detected and to be cautious Microsoft has paused the automatic uninstallation of classic Teams for customers who haven't already completed this step. This issue could result in the Teams Meeting Addin in Outlook failing to schedule or join Teams meetings. We are actively investigating this issue and will update once it's resolved. If your users are experiencing this issue, a workaround is to use Teams to schedule or join meetings.