I want to link the php file to the database, but I face this error:

Warning: mysqli_connect(): (HY000/2002): No connection could be made because the target machine actively refused it in C:\xampp\htdocs\start\hello.php on line 3

But I don't see any problems in the file. File data:

<?php

    if (mysqli_connect("127.0.0.1","root","","university")) {
        echo "yes";
    }

But the information is correct. Please help.***