PhpMyAdmin may encounter a redirect loop where it appears stuck on the page showing "The system will redirect you in a moment."
The issue is cause by mySQL not being able to create a temporary user to access phpMyAdmin. This is reflected in the /usr/local/cpanel/logs/error_log with the following error:
Cpanel::Exception::Database::Error/(XID 9a8sak) The system received an error from the “MySQL” database “mysql”: 1 (Can't create/write to file '/tmp/#sql_5a2_0.MAI' (Errcode: 30 "Read-only file system"))
You can verify the status of the /tmp and /var/tmp file systems by looking at your current mounts:
# mount -l | grep -i "tmpDSK"
/usr/tmpDSK on /tmp type ext4 (ro,nosuid,noexec,relatime,seclabel,discard,data=ordered)
/usr/tmpDSK on /var/tmp type ext4 (ro,nosuid,noexec,relatime,seclabel,discard,data=ordered)
Please see the instructions in the following article: