2. Make sure that you've set correct password for database user in your configuration file.
3. Make sure you've assigned correct user and privileges to database.
4. If you're still receiving the error then please check the error logs. If you're getting error message as below -
1. cPanel >> MySQL Databases >> Repair Database
2. WHM >> SQL Services >> Repair a MYSQL Database >> Select database >> Repair Database
That did the trick for me!
Note :- If you're unable to get the error logs using 'tail -f /usr/local/apache/logs/error_log' then check the MySQL error logs using 'tail -f /var/lib/mysql/hostname.err'