Most likely, the MySQL login credentials have been changed or the provided values are invalid.   

Contact the server admin and obtain the most current MySQL login credentials:

• MySQL host
• MySQL login
• MySQL password
• MySQL database name (database created for the PHP Live! system)

After obtaining the above values, edit the file phplive/web/config.php and update the MySQL values. You will see values similar to:

$CONF['SQLHOST'] = 'the_host' ;
$CONF['SQLLOGIN'] = 'the_login' ;
$CONF['SQLPASS'] = 'the_password' ;
$CONF['DATABASE'] = 'the_db_name' ;

Update the values and save the config.php file. Done!