Locate config.sample.inc.php
Change
$cfg['Servers'][$i]['host'] = 'localhost';
into
$cfg['Servers'][$i]['host'] = '127.0.0.1';
Save.
this happen becuse you may using multipe mysql server on system and
php did not recognized the localhost
and mysql default port is always 3306
try to connect via terminal first
Run =>>
mysql -h 127.0.0.1 -P 3306 -uroot -p
then password
you are in if password is correct