phpmailer says invalid email when parameter passing - php

Question

<?php
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;
require 'PHPMailer-master/src/Exception.php';
require 'PHPMailer-master/src/PHPMailer.php';
require 'PHPMailer-master/src/SMTP.php';
$mail = new PHPMailer();
$mail->IsSMTP();
$mail->Mailer = "smtp";
$mail->SMTPDebug = 1;
$mail->SMTPAuth = TRUE;
$mail->SMTPSecure = "tls";
$mail->Port = 587;
$mail->Host = "smtp.gmail.com";
$mail->Username = "myemail";
$mail->Password = "myemailpassword";
if(isset($_POST['submit'])){
$from = $_POST['email'];
$first_name = $_POST['first_name'];
$last_name = $_POST['last_name'];
$subject = $_POST['subject'];
$message = $_POST['message'];
$mail->IsHTML(true);
$mail->AddAddress("myemail", "name");
$mail->SetFrom($from);
$mail->AddReplyTo($from);
$mail->Subject = $subject;
$content = $message;
$mail->MsgHTML($content);
if(!$mail->Send()) {
echo "Error while sending Email.";
var_dump($mail);
}
else {
echo "Email sent successfully";
}
}
?>
the code works if I enter the details myself rather than getting them from my html form. for example for $mail->SetFrom("myemail", "my name")
tried defining the variable when I call it in the mail function that didn't work either