This error means there is a problem on the server side. A Server Error can be caused by any number of things from uploading the incorrect file to as bug in a piece of code. This error response is a generic "catch-all" response. The web server is telling you that something went wrong, but it's not sure exactly what that is. If you have root access, you should review your web server's error logs to get more information about this. If you are using shared hosting plan, you should contact your host to get more information. The best way to debug the error depends upon the server and what's actually running at the time. Consider some debugging tips to help diagnose and fix common causes of this problem.