what is the 404 error?

I have tried posting so many times today and it has come up with this 404 error so I kept trying thinking it hadn't worked turns out it had so now I look silly with duplicates all over the place, so what does this mean and how do I make it stop

Thankyou is there anyway of deleting these duplicates?

@benny_boy98: Often, the 404 errors are temporary glitches where the server doesn't find the page you attempted to load. If you find one that is persistent, please report it in the Bug Reporting & Feedback forum and help the staff weed them out :)

Regards,

GameSpot Moderation Team