I have a problem in some long-standing WP installations.
In Firefox only, I am stuck in a session timeout/login loop.
I go to /wp-admin/ it shows me the login screen, I login with a known and working username and pass and then it comes back to the login screen again. This is continuous and I often can not login at all.
On occasion when I can login, as soon as I go to save a post, I get tossed to the login screen again.
Additionally If I have more than one tab open on these sites, then I will get the WP session expired dialog. I will login in again via this dialog, but within seconds, the session expired dialog will pop back up.
I have cleared browsers cache, deleted cookies, deactivated cache plugins etc etc,.. but can not find a solution to this issue.
Any help appreciated.