It's hard to help you find a solution if you're not showing the server side code that you have a problem with.
But if you're using Express then you need to use body-parser to be able to access req.body
.
You also need to make sure that your Ember app is sending the right data in the right place and in the right format. Check it with your browser developer tools and post an example request that your Ember app is doing - with path, query, headers and body.
See those answers for more details on how to track down problems like that:
Your question doesn't include enough info to tell you what's the problem with the code that you didn't show but that could at least give you an idea to what to go through step by step.