PhpMyAdmin is failing to load or is continuously redirecting to itself

Symptoms

PhpMyAdmin is failing to load or is continuously redirecting to itself.

Cause 

The internal mysql database cannot be accessed when using PhpMyAdmin. If you check the cPanel error log /usr/local/cpanel/logs/error_log you may see one of the following or similar errors:

CONFIG_TEXT: Cpanel::Exception::Database::Error/(XID 6pga43) The system received an error from 
the “MySQL” database “mysql”: 
1805 (Column count of mysql.proc is wrong. 
Expected 21, found 20. The table is probably corrupted)

CONFIG_TEXT: Cpanel::Exception::Database::Error/(XID fp35yd) The system received an error from the “MySQL” database “mysql”: 1728 (Cannot load from mysql.proc. The table is probably corrupted)

Resolution

To resolve this, you will need to perform a mysql_upgrade.

1. Log in to SSH as the root user, or utilize the WHM Terminal.

2. Make a backup of the MySQL databases

   # mysqldump --all-databases | bzip2 -c > /home/databasebackup.sql.bz2

3. Run the following command:

   # mysql_upgrade

4. Try accessing phpMyAdmin again.