Why can't I see the Microsoft Teams Meeting add-in for Outlook?

We have experienced this issue with the Outlook Teams add-in this week as well with version 1810 (build 11001.20074 click-to-run) and Microsoft Teams Version 1.1.00.29068 (64-bit), last updated on Nov 9, 2018. The add-in has disappeared after the last update even though enabled in the meeting policies. The add-in files still exist in the local folder, but trying to add it back in, as mentioned above, does not work.

Command used to register the DLL was successful:

%SystemRoot%\System32\regsvr32.exe /n /i:user %LocalAppData%\Microsoft\TeamsMeetingAddin\1.0.18261.4\x64\Microsoft.Teams.AddinLoader.dll