Sometimes, when I try to use certain functions on wordpress.com, I get redirected to a login page. After I sign in, I get redirected again to the same login page. This repeats in an endless loop. It usually doesn’t bother me, as I self-host my blog, but for some things, like the yearly annual report that came in about two weeks ago, it does bother me. I looked into the matter, and the issue turned out to be due to blocking third-party cookies. To resolve the endless login loop, you need to add https://wordpress.com (note the https) to the exception list of accepted third-party cookies (in Firefox, it’s under Preferences -> Privacy -> Exceptions).