Also, how did your user install WordPress?
If it was using the one click installer in cwp...It does not work properly anyway and I get thus error with every user account trying to install WordPress from cwp.
This in my case is always because cwp script stuffs up the automatically or manually generated password copy process and adds the stuffed up password to the WordPress wp-config.php file.
This means on every installation of WordPress on my cwp server, it immediately throws a cannot connect to database error.
In my case, fix is easy...manually edit the wp-config.php file password to exactly match the one that was input into the one click installer script. Or set a new password and use that one for the wp-config.php...Then it works.
This problem should not happen in cwp...and I have grumbled about it for a while, however no one at cwp can be bothered fixing it and so the problem remains! The one click installer is useless.