I am developing an application on Teams that simply uses a bot that communicates with an API from my company.

When I try to access the application (Collaborateur), I can't open it and I get this error: Error while adding app

I have already tried to create another very simple application, but the same problem occurs. I contacted Microsoft support but it wasn't a configuration issue and they weren't able to help me more.

Note that I can try the bot on Teams by going to / and clicking on my bot then "Channel" then "Microsoft Teams" and my bot works.