Problems with native HTTP

I’m testing my app with the native HTTP plugin but I’m having some issues. I was using Angular’s HttpClientModule but I decided to give it a try to the native plugin. My code so far isn’t too large, so I just had to change some calls, replace ‘subscribe’ by ‘then’ and my code compiled correctly. However, when the app is started on the device only a blank screen is shown and no console messages or errors (debugging it with Safari web inspector because it’s an iOS device). What am I doing wrong?