Error 403 with POST using ActiveCampaign API- trying to add contact, valid API key

Question

From my understanding by Googling the 403 error means the API key is right but access is forbidden? But I'm not really 100% sure what that means or how to resolve it.

Below is my code that triggers when I press a button (I've manually added the contact data for testing).

Any help is greatly appreciated.

My code:

$.ajax({
      async: true,
      crossDomain: true,
      url: 'https://myactivehost.api-us1.com/api/3/contacts',
      method: 'POST',
      headers: {
        accept: 'application/json',
        'content-type': 'application/json',
        'Api-Token': 'myAPIkey'
      },
      processData: false,
      data: '{"contact":{"email":"npm.jake@gmail.com"}}',
      success: function() {
        console.log('success');
      },
      error: function() {
       console.log('failed'); 
      }
    });