Error 500 ispconfig 3

i recently lost the access to ispconfig panel and i can't seem to find the problem.
the other parts like webmail is functioning well but not the panel. i have it installed on debian 9, apache2 , ispconfig version 3.1.12 .
Could someone help me with this and thank you

 

thank you for replying i got this

 

Did you do that?

 

i checked /var/log/apache2/suexec.log it's empty the logs goes somewhere else?

 

Have you changed owner or permission for files or directories?
See other logs, try to find what is being done when that error happens.

 

thank you for replying sir, there are logs that show ownership and permission changes? i'd like to know which ones and locations and thank you

 

I do not know of logs about file owner or permission changes. You should know whether you have altered them or not. You could compare owners and permissions to the backups you have.

 

edit : i fixed the problem it was on fast-cgi bad permissions, thanks for replying everyone i appriciate the help