Outlook for Mac not showing email

When it was still a beta version I tried the new Outlook for Mac 2 times but each time but of the 2 accounts I have in Outlook (work - private) it would never show the private email (MAPI).

Now the final version is here.... you guessed it, it is not showing my private account. I can see the folders but when I click on them it says 'Loading, this might take a few moments'.

I saw an older topic about this but there the solution was to do the beta view. That is now no longer an option 😞

Ps. I can see this folder in the Old Mac Outlook, Windows Outlook, Iphone email and via the webview of my provider. 

Pps. I have no filters active

Any suggestions on how to make my Outlook work as before this update?