Booking Error Message

I have a strange Problem.

I remember when I tried all the features off the Busniess Apps, I created a bookings calndar and then deleted it later. So now I wanted to show it to a potential customer and I can't access anything.

The error message looks like this and happens as soon as I click on any tab.

"Your request can't be processed. Try it later.

I'm using an global admin account. 

Can someone help me out?