Cannot declare class modResourceCreateProcessor error after moving site

Summary

After moving the site to another server I have an error when I tried to create a new resource. The progress bar doesn’t stop and nothing happened after. In web-server log i see:

[error] 635201#635201: *809 FastCGI sent in stderr: “PHP message: PHP Fatal error: Cannot declare class modResourceCreateProcessor, because the name is already in use in /var/www/site/core/model/modx/processors/resource/create.class.php on line 0” while reading response header from upstream, client: [IP], server: site.org, request: “POST /connectors/index.php HTTP/1.1”, upstream: “fastcgi://unix:/var/run/php/php7.4-fpm.sock:”, host: “hostname.org

I checked all permission and file owners and it looks ok.

Expected behavior

any a meaningful errors from modx. Not just stack on progress bar.

Environment

MODX version 2.8.3, NGINX with version, MySQL version 1.18

does this only happen, when you try to create a new resource?
Editing existing resources works?

Editing existing resources not working also. But other things like templates work well.

To make sure, it is not a plugin, I would try to deactivate all plugins.
You could also try, if a completely new installation works.

Which workflow did you use to move your installation?

Deactivating plugins does not change anything.
I’ll try to set up a new installation on the same server for the test.

I moved all files using tar with all permission and move DB use dump. After move I remove everything from core/cache directory.

To be sure, that I have a clean, unmodified core, I don’t move the old core files, but do a new installation and use that guide:

Migrating Your MODX Site | MODX

Be sure to manually delete all files in the core/cache directory after disabling plugins and before testing the effects of that.