by Ulysses John Cun.
Hello Ken, changing the login/email address worked. Thank you very much!
As for why I upgraded to 4.2.3 is. I upgraded from 3.11.2 to 3.11.8 then to 4.2.3 and planning to upgrade to version 5.
I have another question, is it possible to restore a course along with the enrolled users using the CLI tool (restore_backup.php). Because the restored courses via CLI tool did not include enrolled users. Since I am trying to automate it using the CLI tool because there are 300+ courses needed to be restored.
It works in the web UI by Restore to existing Course > Restore Settings and checking the "Include enrolled users" and selecting the "Yes, always" in the "Include enrolment methods" and enrolled users included after restoring.