[alams]

It looks like the issue is region specific. While I was getting ""Operation failed with unexpected error" when trying to Join a meeting via invite, my counterparts in Europe were able to perform authentication and join meetings without any issues.

[pferde]

I am in central europe, and it doesn't work at all, so perhaps it's just pure luck (or pure bad luck?) when it works for you.

[ju-st]

Germany: Joining a meeting with invite URL worked for some colleagues, others could only join after the the group chat called them directly.

[TheNewsIsHere]

US East. I’m not joking when I say that’s the result about half the time even with no noted service issues.