Access denied for user 'UNKNOWN MYSQL_USER'@'localhost' (using password: NO)

[Pez_del_MySQL _]

I've run into a warning in the logs of MySQL, searching and searching I found the culprit of the warning.

In /etc/init.d/mysqld I found:

STARTTIMEOUT = 120
while [$ STARTTIMEOUT-gt 0] do
RESPONSE = `/ usr / bin / mysqladmin - socket =" $ socketfile "- user = UNKNOWN_MYSQL_USER ping 2> & 1` && break
echo "$ RESPONSE" | grep-q "Access denied for user" && break
if! / bin / kill $ -0 safe_pid 2> / dev / null; Then
echo "failed to start MySQL Daemon."
ret = 1
break
fi
sleep 1
let STARTTIMEOUT = $ {-1} STARTTIMEOUT


I think what it does is try to see if mysql works, am I wrong?
Is there any way to avoid the warning?