I have a brand new server running Plesk 8.0.1 and Horde 3.1.3, but Horde is not working properly. I have not custom installed anything on this server, and I have updated everything to most recent versions using Plesk Updater.

The Horde login screen comes up, but when I enter correct credentials it just refreshes the login page and does not produce any error messages. If I enter incorrect credentials it reports "Login Failed".

I have checked the Horde MySQL database, and the "prefs" table is recording successful logins.

Does anyone have some advice? (New clients on a new server are not very patient nor forgiving.)

Just guessing but maybe there is an issue with php's session functions?

I considered that, so I checked the session variables from within the Horde IMP login authentication functions. The session data was definitely there, but one thing that caught my attention was that the functions kept referring to variables in an array called 'imp' like $_SESSION['imp']['example'], but no 'imp' array was there, instead the variables were just in the root of the session like $_SESSION['example']. That seems like a coding problem in Horde, rather than a PHP issue, but if that was true then everyone would be having this problem.

If it is a brand new server maybe the plesk install was done incorrectly. You may wish to have ev1 restore the box (should be free if it was brand new and the image is messed up) or you could try to remove the horde RPM and reinstall it.

Actually, I did have them re-image it, and I also re-installed the RPMs, but still didn't work. Apparently they have some problems with their disk images.

Very interesting... I installed a second copy of Horde from source, and when I ran the test script I was surprised to see SEVERAL FATAL ERRORS! I had to install a few PEAR modules, and change a bunch of PHP settings. The MOST IMPORTANT setting change was this one:

session.auto_start = 0

So you were right -- it was a PHP sessions problem. I also had to add the PEAR directory to the include path:

include_path = ".:/usr/share/pear"

Now it is finally working properly. Thanks, agruetz, for your suggestions.

Kinda what I figured. As what you said is typical of a php application that requires sessions for login and has them turned off in the php.ini. Anyway glad it is now working.

Actually, Horde requires sessions to be turned OFF in php.ini. Seems counter-intuitive, but apparently it has something to do with session fixation. So the session.auto_start MUST BE TURNED OFF, forcing Horde and other php applications to manually start and manage sessions.

session.auto_start should be off be default if I recall correctly. Anyway all that matters is it works.