Some users get the following error when trying to login to their moodle:
A server error that affects your login session was detected. Please login again or restart your browser
Your session has timed out. Please login again
- check and fix your permissions in moodledata/session -- set it to 0777
- check config.php, it should NOT has any spaces/new lines at the end of code. Repeat this on all moodle php files you lately changed, such as course/lib.php
- In admin > server > session handling > "Cookie Prefix" put something in the Cookie prefix field that is different for each of your moodle sites, and it should improve the issue with multiple sites on the same url.
- test your server's sessions by running session test on http://yourserver/moodle/lib/session-test.php
- check your phpinfo(); if it session handeling is configured correctly or not.