[PRO SITES] I cannot enable plugin

After couple months of freeze of my project I want to enable Pro Sites again, but it gives 500 error and my site is blank.

During the chat we tried:
- plugins conflict
- change php versions
- increase memory_limit to 1024 (max_execution_time is 300)
- debug.log is not updating it, does not show any currect errors

Also site was moved from one host to another. Not sure if this help here.

Thank you