How can GET/POST work properly with Ionic app for Windows 10?

I developed an App to read and write to DB. this app is for Windows 10 desktop app with 64bit.

The problem is get an error when I build the app in Visual studio to release it.

The API is configured as Cross-origin and works good with POSTMAN

ERROR Response with status: 0 for URL: null

How can I fix this problem with cross platform project Ionic, Cordova and Angular?

What is the actual request that is getting this response?
GET, POST, OPTIONS? (look at the dev tools what the actual request is, not what you are writing in your code)