php mail() function not working, been stuck for hours

Question

I can't seem to debug this as this is the first time I've used php. I initially had this setup and it actually worked but I tried adding some more radio buttons and it stopped working. I took the radio buttons out to try to get back to square one, but now I can't even get the simple form to send. I've been staring at it for hours, can you please help me figure out what's wrong. Thank you!

<?php
if($_POST["submit"]) {

    $recipient="testing@yahoo.com";
    $subject="Business Sign-Up Request";
    $senderName = $_POST["senderName"];
    $businessName = $_POST["businessName"];
    $phone = $_POST["phone"];
    $senderEmail = $_POST["senderEmail"];
    $website = $_POST["website"];
    $businessLicense = $_POST["businessLicense"];

    $mailbody = "Contact Name: $senderName\n\nBusiness Name: $businessName\n\nEmail: $senderEmail\n\nPhone: $phone\n\nBusiness License: $businessLicense\n\nWebsite: $website";

    mail($recipient, $subject, $mailbody);
    $thankYou="<p>Thank you! Your message has been sent.</p>";
}
?>

Here is the HTML form that is below the php code...

<?=$thankYou ?>
<div id="TestModal" class="modal fade" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="container">
                <div class="row">
                    <div class="col-12 float-right">
                        <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
                    </div>
                </div>
                <div class="row">
                    <div class="offset-2 col-8 text-center">
                        <h4 class="businessSignUp-title" id="myModalLabel">Business Sign-Up</h4>
                    </div>
                </div>
                <div class="row">
                    <div class="offset-1 col-10 text-center">
                        <h3>Please submit your information and we will contact you shortly!</h3>
                    </div>
                </div>
                <div class="row text-center"> 
                    <div class="col-12 text-center modal-body">
                        <form method="post" action="home.php" class="text-center">
                            <div>
                                <input class="w-100 py-1 px-2 businessSignUp-input mt-2" required name="senderName" placeholder="Name">
                            </div>
                            <div>
                                <input class="w-100 py-1 px-2 businessSignUp-input mt-2" required name="businessName" placeholder="Business Name">
                            </div>
                            <div>
                                <input class="w-100 py-1 px-2 businessSignUp-input mt-2" required name="phone" placeholder="Phone">
                            </div>
                            <div>
                                <input class="w-100 py-1 px-2 businessSignUp-input mt-2" required name="senderEmail" placeholder="Email Address">
                            </div>
                            <div>
                                <input class="w-100 py-1 px-2 businessSignUp-input mt-2" name="businessLicense" placeholder="Business License (optional)">
                            </div>
                            <div>
                                <input class="w-100 py-1 px-2 businessSignUp-input mt-2" name="website" placeholder="Website (optional)">
                            </div>
                            <input class="btn btn-primary mt-4" type="submit" name="submit">
                        </form>
                    </div>
                </div> 
            </div>
        </div>
    </div>
</div>

Answer 1

try to run the code with hardcoded values first to see if mail is working fine i.e only php part not html

<?php
    $recipient="testing@yahoo.com";
    $subject="Business Sign-Up Request";
    $mailbody="test message";
    var_dump(mail($recipient, $subject, $mailbody));
    // echo mail($recipient, $subject, $mailbody);
?>

Answer 2

yes @Kamil007 is right you need host and host must be capable of sending email

check if mail function succeed or not using below code

var_dump(mail($recipient, $subject, $mailbody));