Hello, i have the same problem : just after fresh install of stable 2.3.8 version, i can't login as admin, the page reloads to the login page.
I've tried to login many times, it worked one time only.
OJS is installed in a directory of the web root : /ojs/, i've an .htacces with the rewrite rules.
The Apache log shows many errors of the type : "client denied by server configuration: /home/htdocs/index" (/home/htdocs is the web root path).
Here is the Apache configuration for the /ojs/ directory :
Options Indexes FollowSymlinks
Allow from all
I've checked all ideas i've found in the FAQ and here, to no avail.
The browsers are accepting cookies (and they seems ok, with the real path). I've set the session_check_ip to Off
I've activated the MySQL debug option of the config.inc.php, it seems that the login is accepted then rejected ?
Thanks for your help
Edit : Same pb. with 2.4.1
Edit2 : More info. on the pb. With firebug i looked at the OJSSID cookie, and then at the sessions table. There i found that on the record corresponding to the sessions cookie value, the user_id field was 0, instead of 1 (admin user). When i change that value to 1, i'm recognized as the admin by the site. Not sure if it helps, perhaps the login process can't recognize my credentials ?