This “400 Bad Request” error message, n blank page, when clicking on weblinks within HU posts, has nagged me (and a few others) for awhile. Tried many “fixes” all to no avail.
The problem?
I was auto-logged into HU.
The cure?
Gotta log-out of HU!
So logged-out, cleared cookies, logged-in, and voila! The Weblinks all work! 😊