There seem to be a handful of folks who are having login problems. So far, I think the only thing these folks have in common are using multiple systems to access the forum.
I'm a little fuzzy about how YaBB keeps track of somebody's login status but I think it sets a cookie on your machine. This cookie is also tied to the IP address that was being used when the cookie was created. It's possible (likely) that if somebody logs in on one PC, goes to a different location and tries to log in to the forum, it might get confused and feel a hacker is trying to spoof an IP address as the user's IP no longer matches what was set in the cookie.
I have logged in as several of these users and have had no problems which seems to support YaBB Support's theory that is is a workstation related issue. Support agrees that all of the affected users dump their internet cache and delete all cookies on the affected machines. I also read that web accelerator programs might also cause issues like this.
I have posted on YaBB's Support Forum and am trying out suggestions so if any of you have had this problem, and it's mysteriously went away let me know. I have also inquired as to whether there is an internal YaBB mechanism I can invoke to manually modify a user's login status (as far as YaBB is concerned).
Apparently the new forum software handles logins differently from before, perhaps this is an unintended result of trying to close loopholes that hackers and spammers exploit.
