PROBLEM
I can access the Control Panel login, but after entering my username and password, which I know are correct, I’m redirected to the same page.
This started to happen after I changed the cookie settings on the Security and Session Preferences page to both use “cookies only”. I also added a domain for the cookies.
I’ve cleared the cache and settings in Firefox. I’ve also tried Safari, Opera and a PC running IE and Firefox.
I just updated to EE 2.1 earlier this week from EE 2.0 and had no problems after the update. It must have something to do with the cookies.
The problem in this post (http://ellislab.com/forums/viewthread/71321/#352123) is similar to mine, but the solution doesn’t work. I think it only applies to EE 1.x.
How do I change the cookie settings without logging into the control panel?
SOLUTION
I added the following lines to the config file and was able to login:
$config['admin_session_type'] = "cs";
$config['cookie_domain'] = "";