Hey there, Stefan–nice to see you again. 🙂
Sorry for this issue, I can see how that would be frustrating. Does the same thing happen when you try to export other post types as well, or just when trying to export events?
It’s a bit of a long shot (though still a possibility), but I see you noted that you are currently running version 3.8.1 of the plugins. Are you able to update to the latest versions of both The Events Calendar and The Events Calendar PRO? We’re currently at version 3.9.1.
Let’s start there and see what we find.
Cheers!
Geoff