Validation of Anti-XSRF token failed.

Validation of Anti-XSRF token failed. [InvalidOperationException: Validation of Anti-XSRF token failed.] SportGather0963.SiteMaster.master_Page_PreLoad(Object sender, EventArgs e) +396 System.Web.UI.Page.OnPreLoad(EventArgs e) +121 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +699 What does this even mean? And how do i fix it?

I created a user with the classic registration form that is provided by default and then when i played a bit with the login logout i realised that even if i had pressed log out and i was transfered back to the home page the indication was still showing logoff .
I pressed logoff again and then this error appeared. Please help i cannot find any help in the internet about it.
...