My Get Request Works on Browser, Fails on Mobile

I have a project which front end is angular backend is .net core web api and i am using Cordova to convert this project to APK. But i have a big problem. My GET request works well on browser (which i used ‘cordova run browser’ command) but when i try get request on mobile, nothing happens. I am assuming that my backend works on localhost. My browser can access local host but my Android Studio Emulator phone can’t access localhost. How can i fix that? Please help me thank you!

This is my code piece where i try to get request.

  ngOnInit() {

    document.addEventListener("deviceready", this.onDeviceReady, false);
    this.onBrowserReady(); // TEST BROWSER
  }

  onDeviceReady() {
    alert(1)
    cordova.getAppVersion.getVersionCode(function(version) {
      alert(2)
      this.versionService.GetNewVersion().subscribe(x => {
        alert(3);
        this.object2 = new Object();
        this.object2 = x;
      });
    });


  }

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