I am having a most puzzling problem. I can't login only with FireFox 1.5.0.12 on Mac OSX10.4.9. It just started an hour ago. No problem until then. I need to stay with v1.5 on this machine, by the way.

When I try logging in, it attempts to transfer data then all the sudden Garland's right side bar, where the login is, refreshes, and sits there. If I try login from /?q=user I get 403 error. Huh?

I disabled caching, deleting cookies, powercycle everything (just in case) but to no avail. I am running out of options, but I can't say I know FireFox that well so I might be missing something.

Safari is fine. Opera is also fine on this very same machine. FireFox is the only one. On my WinXP machine, the same FireFox version is doing just fine. Something I did upset this particular FireFox?