I have two D6 installations on the same server. They was working fine, but the server on which they were running had a disk failure, so the installation was moved to a newer server. On the new server, the Drupal sites appear to display fine (I have two different sites under separate installations). However, none of the users can access the admin pages.
When I log in with the correct credentials, I get an Access Denied message on the subsequent user page. The authentication appears to be successful -- if I enter incorrect credentials, I get an incorrect credentials message.
After login, and after the Access Denied message on the user page, if I then manually navigate to an admin page, I am still greeted with the Access Denied message, as though I'm not logged in.
phpMyAdmin runs fine on the server. A custom (non-Drupal) PHP web app with PEAR-based authentication runs fine.
I have examined my php.ini file -- with the exception of changing some basic parameters (max post/upload sizes, location of MySQL socket), it's fairly in line with defaults. MySQL seems to be configured fine, mostly default. I am on Mac OS X Server, using a custom MySQL installation through MacPorts along with the OS-supplied PHP / Apache setup. As for client-side, I have completely reset Firefox and cleared cookies/cache from Safari -- I see this behavior on Mac / Windows and Safari / Firefox / IE. I have truncated my Drupal sessions table. The settings file has a cookie domain set to accept the default.
I am at a loss as to why both Drupal installations are exhibiting this behavior. They use some of the same modules, but their setups are not identical.
I really can't seem to identify what I should be looking for when trying to figure out why my sessions aren't recognizing that I have successfully authenticated. Does anybody have any suggestions for where I should be looking?