An error occurred while saving the commentTim commented An error occurred while saving the commentTim commented
Microsoft Support helped me fix this. Our problem was that our email security gateway was rewriting the URLs in a Teams Meeting invitation. This explains why it only happened for externally organised meetings - internal invitations didn't have the URLs rewritten.
Also it worked OK when the text based link was clicked because the browser would attempt to access the rewritten link and be redirected correctly. However when you click on the Join Online button Outlook passes the URL direct to Microsoft Teams, and Teams doesn't even try to access the URL because it doesn't recognise it as a https://teams.microsoft.com... address.
Added an exception so https://teams.microsoft.com/* URLs aren't rewritten and problem solved. Hope this helps someone.
Group Calendar is a priority for the team, and the feature team is continuing work on it. You’ll start to see some incremental improvements. We look forward to sharing more details and timeframes soon.