Delete action not working

I'm trying to learn ember.js by following Getting Started with Ember.js Using Ember CLI. The tutorial shows you how to build a todo list but I'm having trouble getting the delete action to work. Since I'm new to ember, I'm not 100% sure what code you guys will need to see but the delete button is in app/templates/components/todo-item.hbs:

{{#if editing}}
    {{input class="edit" value=todo.title action="submitTodo"}}
{{else}}
    {{input type="checkbox" checked=todo.complete class="toggle"}}
    <label class="{{if todo.complete 'completed'}}" {{action "editTodo" on="doubleClick"}}>{{todo.title}}</label>
    <button class="destroy" {{action "deleteTodo"}}></button>
{{/if}}

I have a delete action in app/components/todo-item.js like so:

  actions: {
    editTodo() {**code**},
    submitTodo() {**code**},
    deleteTodo() {
      let todo = this.get('todo');
      this.sendAction('deleteTodo', todo);
    }
  }

And in app/routes/todos.js I have:

actions: {
    createTodo(newTitle) {**code**},
    updateTodo(todo) {
        todo.save();
    },
    deleteTodo(todo) {
        todo.destroyRecord();
    }
}

When I click on the delete button nothing happens and the following shows up in Ember Inspector console:

Successful request: DELETE /todos/2

Object (with a lot of stuff nested under it)

Error: Assertion Failed: normalizeResponse must return a valid JSON API document: * One or more of the following keys must be present: "data", "errors", "meta".

I'm not really sure what that error means so if anyone could explain and offer a possible solution I'd really appreciate it.