Cannot connect to 365 business calendar and Teams, says personal but it is not.

Cannot connect to 365 business calendar and Teams, says personal but it is not.

hi

I have a number of users connected to their 365 business accounts. Adding a new user and it thinks hes got 365 personal edition. He does not....

Anyone know what's going on. Trying for days now. 

Bookings go into his MS calendar but as its thinks its "personal" you can not add Teams.