If the teams Add-in is not displayed in outlook, please do the following steps.
- Go to: Outlook > File > Options > Add-ins
- Check to see if Microsoft Teams Meeting Add-in is listed under Active Application Add-ins
- If not listed, press Go button and in Add-ins available mark the checkbox or search for it to add it.
If the Add-in is available do the following steps below.
- Close Outlook
- Sign-out from the Teams app
- Close completely Teams app
- Start the Teams app
- Log in to Teams
- Start Outlook and check if the Teams meeting add-in appears in calendar.