Solution 1:

To access your PC localhost from Android emulator, use 10.0.2.2 instead of 127.0.0.1. localhost or 127.0.0.1 refers to the emulated device itself, not the host the emulator is running on.

Reference: https://developer.android.com/studio/run/emulator-networking#networkaddresses

For Genymotion use: 10.0.3.2 instead of 10.0.2.2