"You'll need a new app to open this about link"

kemaltolga I had the same problem. Oddly (or maybe intentionally), every time I clicked a Teams Meeting "join meeting" link in a gmail message, Chrome opened and I received a message that no default app exists for handling this type of file (msteams). After many attempted fixes, I decided to forward the gmail to my outlook.com email account; when I clicked on the same "join meeting" link within the outlook app, Edge opened, the file handling notice did not pop up, and I was able to connect to my Teams meeting. I have repeated this experiment with the same results.