How to fix net::ERR_SSL_PROTOCOL_ERROR in Ember REST Adapter

I'm making an EmberJS application on port 4200 using Ember-Cli but it's using a database on port 8080. In my rest adapter, I overwrote find method (just to get something working) like this

find: function(store, type, id){
   return this.ajax('http://localhost:8080/api', 'GET');

}

which is the same as the original find method except that I replace the call to buildURL with a string representation of the host I want to call. Although on the server I explicitly allow cross origin requests, I'm getting a net::ERR_SSL_PROTOCOL_ERROR in the chrome browser. Furtherdown in the error message stack, there's reference to an EMBER.RSVP.Promise.hash.error... In my route, I use Ember.RSVP.hash like this

   model: function(){
         return Ember.RSVP.hash({
           store: this.store.find('mymodelname')
       })

   }

What can I do to make this GET request work?