Slide 18 - Problems You will encounter when using .htaccess files (Internal Server Error 500) § Session 11 - Server-Side: HTTP and Apache Web Server Configuration

500 Internal Server Error
If you see begin seeing 500 Internal Server Error responses from the server after you have created or edited an .htaccess file, the most likely cause of the problem is incorrect permissions and/or an error in the directive syntax.

Permissions on the .htaccess file are not set correctly. Just like HTML and image files, the server must be able to read the .htaccess file. The simplest way to allow that is to make your .htaccess file readable by "other".

cscie12students% pwd
/home/courses/j/h/jharvard/public_html
cscie12students% ls -l .htaccess
-rw-------   1 jharvard  founder         349 Nov 27 00:03 .htaccess
cscie12students% chmod o+r .htaccess
cscie12students% ls -l ~/public_html/.htaccess
-rw----r--   1 jharvard  founder         349 Nov 27 00:03 .htaccess

Syntax Error. An error in the syntax of a directive the .htaccess file will result in a 500 Internal Server Error. In addition, correct usage of a directive that is not allowed in the .htaccess file will result in a 500 status code. Whether or not a directive is allowed depends upon the server configuration file (httpd.conf; AllowOverride) and the directive itself.