Solved
Delete temp/cookies.
If anyone is getting a 401 HTTP error when trying to sign in, be sure to delete your cookies and tempory files. That worked for me.
Forum Discussion
Requires you to sign in almost every day still though. I wonder what the experiation date on the cookie is? I tried to look but couldn't find the right cookie.
When testing new forum stuff, I tried canceling a "Like" and it caused an untrapped error that resulted in the 401 HTTP error. Closing all browser tabs cleared it and it hasn't occurred since. The untrapped error that caused it has apparently been fixed. If you're still getting the 401 error every day, you might have a unique issue. The following website might help, but it may be stuff you already know.
