Internal server errors can be caused by a few different things. Please check the Error Log in cPanel for specific information.
Here are the most common reasons for 500 errors:
1. Bad permissions, Writable by group
Directories and folders should be 755. Executable scripts within the cgi-bin folder must be 755. Images, media, and text files like HTML should be 644.
2. Bad .htaccess, Invalid command
In the (dot)htaccess file, you may have added lines that are either worded badly or conflicting. The best way to troubleshoot this is comment out the lines in the htaccess.
You can comment out a line in the .htaccess by adding # to the beginning. You are wise to save an original copy of any file before you make changes.
For example, if the .htaccess looks like:
DirectoryIndex default.html
AddType application/x-httpd-php5 php
Then try something like this:
DirectoryIndex default.html
#AddType application/x-httpd-php5 php
