Several of our users have reported that they are missing icons for Teams Meetings in Outlook.
As you can see from the picture above, the Teams Meeting icons are located in the Home menu of Outlook Calendar. Teams Meetings add-on is integrated into Outlook with Microsoft Teams meeting Add-in for Microsoft Office. Once I clicked File in the Outlook menu I selected Slow and Disabled COM Add-ins.
I could see that Microsoft Teams meeting Add-in for Microsoft Office add-in was disabled because of a startup delay of 0.70 seconds or more possible because of an issue that caused the Outlook client to crash.
In order to solve this, select Always enable this add-in radio button and click Apply.
On the next screen, you can choose to Always monitor this add-in if you would like to track possible repeating issues right away, or select not to monitor the add-in for the next 7 or 30 days.
If you continue to experience issues with the Add-in it is advisable to completely uninstall Teams client as we explained here and then do a fresh install of the latest version of Teams client which comes packed with the add-in.
Hope this helps.