[php] PHP Warning: mysqli_connect(): (HY000/2002): Connection refused

I am using PHP 5.5 and MAMP (downloaded from here):

I have a basic script like this:

<?php
$servername = "127.0.0.1";
$username = "root";
$password = "root";

// Create connection
$conn = mysqli_connect($servername, $username, $password);

// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}
echo "Connected successfully";
?>

and when I run this script I get this error:

PHP Warning:  mysqli_connect(): (HY000/2002): Connection refused in /Applications/MAMP/htdocs/test/test.php on line 7

Is there some configuration issue that I need to set up within MAMP or PHP?

For me to make it work again I just deleted the files

ib_logfile0

and

ib_logfile1

.

from :

/Applications/MAMP/db/mysql56/ib_logfile0 

Mac 10.13.3
MAMP:Version 4.3 (853)

Sometimes you need to include mysql db port id in the server like so.

$serverName = "127.0.0.1:3307";

You have to change the mamp Mysql Database port into 8889.

In my case I was using XAMPP, and there was a log that told me the error. To find it, go to the XAMPP control panel, and click "Configure" for MySQL, then click on "Open Log."

The most current data of the log is at the bottom, and the log is organized by date, time, some number, and text in brackets that may say "Note" or "Error." One that says "Error" is likely causing the issue.

For me, my error was a tablespace that was causing an issue, so I deleted the database files at the given location.

Note: The tablespace files for your installation of XAMPP may be at a different location, but they were in /opt/lampp/var/mysql for me. I think that's typical of XAMPP on Debian-based distributions. Also, my instructions on what to click in the control panel to see the log may be a bit different for you because I'm running XAMPP on an Ubuntu-based distribution of Linux (Feren OS).

In WAMP, right click on WAMP tray icon then change the port from 3308 to 3306 like this: