The JSON response could not be parsed in Panel

Do you know this problem?

The JSON response could not be parsed

Service Unavailable
The server is temporarily busy, try again later!

My hoster is not able to help me. Neither does the debug mode.
It’s 3.9.2 running on PHP 8.1.16. I have the same setups on the same hoster multiple times and it works. I also have a local clone of the site which works fine. What I can say, the frontend is running fine, it’s just the panel. I can click the message away and then I see a half way loaded panel with partly emty fields. I compare the write-read-settings on the content and the blueprint folders with another project. No differences there.

What can I do?

They where able to fix it just right now. Thanks for your feedback anyway. I made a mess with a cronjob for an automatic backup and that stuffed up the RAM. The first guy I had on the phone was apparently not quite fit enough to interpret the logs correctly. And I wasn’t anyway.