Manually Reinstall Microsoft Teams Add-in for Outlook

• Ensure Teams and Outlook are fully up to date.
• Use the “Apps” feature to remove the Teams Add-in for Outlook
• Close Teams and Outlook
• Go to the Teams App folder under C:\Program Files\WindowsApps\
• Run MicrosoftTeamsMeetingAddinInstaller.msi
• Launch Teams
• Launch Outlook
• Check that the add-in is now installed, and that the Teams button is on the ribbon.

Reddit Post with helpful links