Hello Thorben

Firstly, I would like to sincerely apologize for the delayed response as we have been experiencing an unusually high number of tickets. I am sorry that it has taken longer than usual to respond to your concern and your patience is highly appreciated.

I would need to remote into your website, and see what's going on.

Please provide me FTP access credentials, and a temporary WP-admin login for your site where this happens, so we could log in and take a look ‘from the inside’ as that’s the most efficient way to see and resolve the issue. 

We do not interfere with any data or anything else except for the plugin (in case that’s a production version of the site), and of course we do not provide login data to third party. 

You can write credentials here just check Private Reply so nobody can see them except us.

Thank you Thorben

There were some foreign keys missing in your database. I had to install WP phpMyAdmin plugin, and manually add the foreign keys, so events are connected to other tables (working hours, employees, schedule, etc.). Once I did that, all events came up.

Please check it out and let me know if everything works now. Also, please feel free to delete the WP phpMyAdmin plugin if you don't need it.

Hi again Thorben

This should not happen again if you don't delete the tables from your database. While those tables remain intact, you should have no more issues like this.