Hi,
In most cases it is either a
permission error or a
bad command in the .htaccess file.
Having 777 permissions on your scripts or the directories they reside in will cause a "500 internal server error" when attempting to execute them. Phpsuexec will refuse to write or read on directories set with such permissions.
Again, using .htaccess with the required PHP prefix of "php_value" will also cause a 500 internal server error. All "php_value" directives should be removed from .htaccess files to avoid the error. Instead, you can create and use your own local php.ini file to manipulate the desired php settings.
In case you've already reviewed the files to confirm about the two possible reasons for the error, I can only ask you to supply us with the domain name on your server that is facing the issue.
Alternatively, you can initiate a Live Chat from our website
UK Web Hosting, Website Hosting, Web Hosting UK, Web Hosting and get this resolved.