CORS issue : AngularJS POST Fails: Response for preflight has invalid HTTP status code 404

Hello guys, so I’ve 2 applications running on ec2.

First one is mainly used for calling services upon ( using mongo, angular, express.js)

Second one has the whole UI (Ionic ) and it calls the other one for the data.

How can i run the CRUD operations on ionic ?

Also can someone please suggest me how to resolve this CORS issue in IONIC app ?