[SOLVED] Mailbox name not allowed. The server response was: Envelope FROM 'example@example.com' email address not allowed

Mailbox name not allowed. The server response was: Envelope FROM 'example@example.com' email address not allowed

I'm trying to make a contact form on my website with SMTP JS. However, when I submit info into the form it's not working outputting error message: "SMTP JS Contact Form Says "Mailbox name not allowed. The server response was: Envelope FROM 'example@example.com' email address not allowed."

Here is my code: HTML:

  <form onsubmit="send(); reset(); return false;">
            <input placeholder="First Name" required id="first-name"><br>
            <input placeholder="Last Name" required id="last-name"><br>
            <input placeholder="Email Adress" required id="email"><br>
            <button>Submit</button>
        </form>

SMTP JS

<script src="https://smtpjs.com/v3/smtp.js"></script>
<script>
var send = function() {
    Email.send({
    Host : "smtp.elasticemail.com",
    Username : "example@example.com",
    Password : "My Password",
    To : 'example@example.com',
    From : document.getElementById("email").value,
    Subject : "New Signup!!!",
    Body : "And this is the body"
}).then(
  message => alert(message)
);
};
    </script>

I've tried moving the website to https server as well as localhost. How can I fix this?

Solution

Many of the answers here helped point me in the right direction but not fully addressed the problem. The actual answer is the comments:

I put my actual email as Username and From and it worked on the spot. Are you still getting the same error message?

_{Thank you @user573431}

The problem here is that I was sending from any email that was not my own. The From and ReplyTo must be your email registered in SMTP.js. Hope this helped someone out!