While in a call, add another person to the call
I know this is marked "complete" in another item (with 404 votes), but you cannot add an additional caller to an existing calling if it is PSTN. This is fine if you are adding a Teams caller to an existing Teams Call.
Mark Kaplan commented
As the poster states, this request was closed with 402 votes as completed however we cannot join a pstn an incoming pstn call to an existing pstn call. https://microsoftteams.uservoice.com/forums/555103-public/suggestions/16952083-while-in-a-call-add-another-person-to-the-call
Jon Webster commented
I thought it was fixed but Just experienced it again today. If the original 2 participates are in teams you can add a 3rd PSTN person. However,
When the original 2 participants is 1 teams user and 1 PSTN user, adding another person to the call is not an option.
You closed the old one, but this is not in place!