6794
I had a similar problem today, i.e. I could login (i.e. my login was accepted), the system thanked me for login, but then it went right back to the login screen.
My problem is that I wanted to extend the time of a session to 60 minutes. In the Options it is being said:
Maximum duration of session idle time in minutes (Valid only when 'use custom session' is enabled. Works only when you are using PHP4.2.0 or later.)
So I enabled the "Custom Session", and I guess, that's where the problems started.
I used phpMyAdmin and changed it the value back to "No", and now it's working again.
I'm not sure if this helps, but you might check the value on your installation.
Also, somebody suggested to empty the session table, see here:
https://xoops.org/modules/smartfaq/faq.php?faqid=248