I can't edit a pending sheet.

[Alefy San]

I'm trying to edit the name of a pending sheet on the Spriters Resource but there's an error. I've tried switching browsers but it still doesn't work. When I click on "submit", it shows a black screen with a text saying "http error 500 this page is not working at the moment". This may be a stupid question but I don't know what that error means. Is it a problem with my internet, or is it error on the site?