I'm new to Moodle.
I installed Moodle like this:
Apache 2.24.43 (https)
PHP 7.3.18 (PHP-FPM)
Redis 5.0.3 (igbinary, phpredis) for sessions
Moodle 3.8.3 (CLI installation from Git Repo)
Login with Custom OAuth2 Server from SIS. (session records are generated well in Redis when users login, and no problem to log in)
Moodle Web Service API functions are called frequently to sync info with SIS.
Now testing with instructors, but some teachers are reporting that they are kicked out of our moodle site so they have to login again and again. This does not happen for other actions like browsing info in the site, but interestingly DOES only when they TURN EDITING ON in their courses, or when they change some settings for the courses such as grading options. It never happens to me as a site admin.
Error Code: error/moodle/confirmsesskeybad
"This error occurs when you have an invalid unique session key. This is usually caused by hard-coding a Moodle URL into your course / site or by an attempt to circumvent the session key"
What does "This is usually caused by hard-coding a Moodle URL into your course / site" mean?
How can I check whether it is or not?
FYI, this happens after I changed cron job period from 3 * * * * (1:03, 2:03, 3:03, ...) to * * * * *. (1:01, 1:02, 1:03, ...), but doubt it's related.
Please Help! Any Suggestions will be so appreciated.