Which username/password do I use to connect to mySQL - php

Question

So, I'm SUPER new to mySQL. Having issues connecting to my database with PHP. Hoping someone can point me in the right direction.
I can login to our Cpanel using my username/password. Using the web gui I was able to create a database.
Now when I try to connect to the database (or even just the server for that matter) using PHP I get an error:
Warning: mysqli::__construct(): (HY000/1045): Access denied for user 'username'#'servername' (using password: YES) in /home/ropepart/public_html/techportal/sandbox/mysqltest.php on line 8
Connection failed: Access denied for user 'username'#'servername' (using password: YES)
To me, it seems like this is a username/password error. But I an using the same username/password that I use to login to the web gui. Why can I successfully login there, but can't login with PHP?
Here's my code (taken pretty much directly from W3Schools):
<?php
$servername = "servername";
$username = "username";
$password = "password";
// Create connection
$conn = new mysqli($servername, $username, $password);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
?>
(Hopefully it's obvious that I've changed my servername/username/password for the purposes of this post)

Answer 1

Check the details correctly, By deafult
host = localhost
username = root
password = (No password leave it as empty)
database = (your database)
<?php
$connection = new mysqli('host','username','password','your_database');
if($connection->connect_error || $connection->error){
echo "error";
}else{
echo "done";
}
?>

Answer 2

you should add database name.
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "demo"
// Create connection
$conn = new mysqli($servername, $username, $password,$dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
?>
//if you are using xampp you shoul locate this file you get information from this
passwords.txt

Answer 3

MySQL database username/password is not necessarily same as cPanel username & password.
Here is what you should do:
Login to your cPanel
From dashboard click "MySQL® Databases"
Add a new user from there (https://prnt.sc/kpiby9). Just fill username
and password (note down the password).
Add that user with your database by selecting both from the dropdown
(https://prnt.sc/kpidqx)
Now, use this username & password to connect with the database.
mysqli_connect(serverhostname,username,password,dbname);