A 500 Internal Server Error is a generic error code displayed by a Web server when a more appropriate error code does not exist. It can be difficult to troubleshoot this error code because many different issues can trigger it.
The HyperText Transfer Protocol defines many error codes for displaying information about specific errors to users accessing a Web server. Examples include the 404 Not Found for a missing file, which often indicates that a user has typed in an incorrect Web address or is attempting to access a deleted file, and the 503 Service Unavailable error that is displayed when a Web server is overloaded with traffic or processes. However, not all possible conditions have defined error codes in the HTTP standard, so Web servers return a 500 Internal Server Error if there is no defined code for the particular error that has occurred.
A diverse array of issues can cause a 500 Internal Server Error. It is rare, though not impossible, for problems with the computer connecting to the server to trigger this error. Faulty scripting on a Web page is a common cause of this error, such as if a form fails to correctly handle a missing or incorrect value. This error can also indicate a literal server error, such as a failed disk or a non-functional server software module.