Connection and query failures.
ERROR ESTABLISHING A DATABASE CONNECTION
The credentials in the configuration file do not match what exists, the database user lacks privileges, or the database server is unreachable.
Compare the configuration against cPanel > MySQL Databases. Remember the username prefix on both the database and the user.
Recreate the user and reassign privileges if unsure.
ACCESS DENIED
The user exists but is not assigned to that database, or lacks the required privileges. Assign with all privileges.
TABLE DOES NOT EXIST
An incomplete installation, an incomplete import, or a prefix mismatch between the configuration and the actual tables.
Check the table prefix in the configuration against what phpMyAdmin shows.
TOO MANY CONNECTIONS
The application is opening connections and not closing them, or several applications are competing.
Check for a connection leak. Restarting resolves it temporarily; the cause needs fixing.
TABLE MARKED AS CRASHED
Repair it through phpMyAdmin. If it recurs, open a ticket.
TIMEOUT ON A QUERY
Usually a missing index on a table that has grown.
