reference:HTTP errors

HTTP error codes

USOC uses some of the standardized HTTP error codes.

Errors with an error page

Code	Description
400 - Bad Reque	If the request couldn't get proceesed because of errors on the user side
403 - Forbidden	If the currently logged in user has no access to the requested resource
404 - Page not found	If the requested page couldn't be found
410 - Gone	If the requested page couldn't be found, but it was there at some point (Like taking a page offline)
414 - URI Too Long	The request URI is too long
423 - Locked	The requested page is currently locked
429 - Too many requests	The client made too many requests in a amount of time
451 - Unavailable For Legal Reasons	The requested resource is unavailable in the country of the user. (For a something that is blocked around the world use 410)
503 - Service unavailable	The requested feature is currently not available or blocked

Errors without an error page

Code	Description
200 - Ok	Everything went normal
301 - Moved Permanently	This resource is outdated. The new resource can be found in the location field
308 - Permanent Redirect	This resource is outdated. The new resource can be found in the location field. The request method keeps the same