How to send data from Klavio Form to SMSBump

Hi everyone, I am trying to send data from Klavio form to SMSBump with JavaScript but nothing works.

It’s my JS:

window.addEventListener("klaviyoForms", function(e) {
  if (e.detail.type == 'submit') {
  var phone = e.detail.metaData.$phone_number;

  if (phone !== '' && phone !== undefined) {
	fetch('https://api.smsbump.com/v2/formsPublic/subscribe', {
	  method: 'POST',
	  body: JSON.stringify({
	  'form_id': 33330,
	  'phone': e.detail.metaData.$phone_number,
	  'country': 'US',
	  'email': e.detail.metaData.$email,
	  'source':  e.detail.metaData.$source
	  }),
	headers: {
	  'Content-Type' : 'application/json',
	  'x-smsbump-platform': 'shopify',
	 }
    })
	.then(response => {
	  console.log(response);
	  response.json();
	});
  } else {
    console.log('Phone is empty');
  }
 }
});

In the console->network->subscribe(name resourse)->preview, I get:

message: "You need to fill in one of the fields."

What could be the reason?