Ember Doesn't Send Additional Headers

Hi everyone, i want to send custom headers, have tried few things but none of them worked.

//in my application adapter, i have added the following

headers: Ember.computed('session.data.authenticated.token', function() {
	return {
		'header_name': ' header_value '

//i have overwritten 'ajax' service to include headers
import Ember from 'ember';
import AjaxService from 'ember-ajax/services/ajax';

export default AjaxService.extend({
  session: Ember.inject.service(),
  headers: Ember.computed('session.data.authenticated.token', {
    get() {
      let headers = {};
      const authToken = this.get('session.data.authenticated.token');
      if (authToken) {
        headers['JWT'] = authToken;
      return headers;

 //in my /dashboard route, i made an ajax request to see,
        method: 'GET'
      let token = this.get('session.data.authenticated.token');

None of these custom headers shown up in req.headers.What should i do to fix this? TIA