Problem z formularzem email

Witam,
Dlaczego formularz nie wysyła wiadomości?

HTML:

            <form onsubmit="sendEmail(); reset(); return false;">
                <h3>zostaw wiadmość</h3>
                <input id="email-name" type="text" placeholder="twoje imię" required class="box">
                <input id="email-from" type="email" placeholder="twój e-mail" required class="box">
                <input id="email-subject" type="text" placeholder="temat" required class="box">
                <textarea id="email-message" placeholder="treść wiadomości" required class="box" cols="30" rows="10"></textarea>
                <input type="submit" value="wyślij wiadomość" class="btn">
            </form>

      <script src="https://smtpjs.com/v3/smtp.js"></script>

JS:

function sendEmail() {
  Email.send({
    Host: "smtp.gmail.com",
    Username: "xxxxxxxxxxxxx",
    Password: "yyyyyyyyyy",
    To: "zzzzzzzzzzzz",
    From: document.getElementById("email-name").value,
    Subject: document.getElementById("email-subject").value,
    Body:
      "Imię: " +
      document.getElementById("email-name").value +
      "<br> Email: " +
      document.getElementById("email-subject").value +
      "<br> Wiadomość: " +
      document.getElementById("email-message").value,
  }).then((message) => alert(message));
}

Dodam, że uruchamiając strone przez live server dostaję taki komunikat:
The specified string is not in the form required for an e-mail address.

Poprawiłem kod, jednak formularz nadal nie działa...
Komunikat:
The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.0 Authentication Required. Learn more at - Fix: Try a different SMTP server : https://elasticemail.com/account#/create-account?r=20b444a2-b3af-4eb8-bae7-911f6097521c

            <form method="post"">
                <h3>zostaw wiadmość</h3>
                <input id="name" type="text" placeholder="twoje imię" required class="box">
                <input id="email" type="email" placeholder="twój e-mail" required class="box">
                <input id="subject" type="text" placeholder="temat" required class="box">
                <textarea id="message" placeholder="treść wiadomości" required class="box" cols="30"
                    rows="10"></textarea>
                <input id="btn" type="submit" value="wyślij wiadomość" class="btn">
            </form>

const btn = document.getElementById('btn');
btn.addEventListener('click',function(e) {
  e.preventDefault()

  const name = document.getElementById('name').value;
  const email = document.getElementById('email').value;
  const subject = document.getElementById('subject').value;
  const message = document.getElementById('message').value;
  const body = 'Imię: ' + name + '<br/> Email: ' + email + '<br/> Temat: ' + subject + '<br/> Wiadomość: ' + message;

  Email.send({
        Host: "smtp.gmail.com",
        Username: "xxxxxxxxxxxxx",
        Password: "xxxxxxxxxxxxx",
        To: "xxxxxxxxxxxxxx",
        From: email,
        Subject: subject,
        Body: body,
      }).then((message) => alert('Wiadomość wysłana'));
})