Can you enable Joomla debug mode so we can see where the error arises?

Is could be because you are using an invalid date formatting option

Did you recently upgrade the server to PHP 8.2?

Hi, debugging information doesn't give us more information, did changed it within configuration.php and within joomla, but both same result. We are using PHP 8.1, switching to 7.4 or 8.1 doesn't change the issue.
Let me know what further info you need!

Joomla debug mode should give the full trace of files and errors where this arises.

This build should catch this error and output the error message

If we don't get useful information from this build can you give me login details on the private site details tab below to check what is going on?

Hi Geraint,

So I need to install a additional plugin within the appendix you did send?

If you install the version of JEvents in my previous post and open the page again it should give you more detailed information about the problem

Hi Geraint,

Installing the extension file seems to be solve the issue
Thanks for your help!

Roland