This is a general error class returned by a web server when it encounters a problem in which the server itself can not be more specific about the error condition in its response to the client.
In many cases this is not an indication of an actual problem with the server itself but rather a problem with the information the server has been instructed to access or return as a result of the request.
If you have made changes to the file ownership on your own through SSH please reset the Owner and Group appropriately.
The server generally expects files such as HTML, Images, and other media to have a permission mode of 644.
The server also expects the permission mode on directories to be set to 755 in most cases.
(See the Section on Understanding Filesystem Permissions.) In the .htaccess file, you may have added lines that are conflicting with each other or that are not allowed.
This error is often caused by an issue on your site which may require additional review by your web host.
Please contact your web host for further assistance.
There are a few common causes for this error code including problems with the individual script that may be executed upon request.
Some of these are easier to spot and correct than others.