HTTP codes
Internal server error
The address was fine, the code behind it failed while building the page.
Also called: internal server error, server error, crash
500 is the status code for a server that failed while building the page. The address was fine. The code behind it was not.
Where you meet it
Reloading rarely helps, because the fault is on the server and not in your browser. On a maintained site an error like this raises an alert before a customer has to report it.