php catch mysqli_connect(): (HY000/1045): Access denied
$conn = mysqli_connect( '<server>', '<username>', '<password>', '<database-name>');
if (!$conn) {
// whatever processing you want to do upon error in connection
// like log error or send an email to admin
// I am just printing the error at the moment.
echo mysqli_connect_errno() . ":" . mysqli_connect_error();
exit;
}