Hello, I started an application with ionic 4 by CLI, the very basics.
Commands used:
== > $ ionic start app-build blank --type = angular
== > $ cd app-build
== > $ ionic cordova platform add android
== > $ ionic cordova build android
So long so good! I get the app with the $ ionic serve command to see if there is any good JavaScript error and you do not have it.
I download the app to my device: Moto G1 | Android 4.4.4 and install it. When I run the app it opens a dialog box with the title: Application Error and with the following error: net :: ERR_CONNECTION_REFUSED
OBS: I tested on a device: Samsung J5 | Android 6.0.0 and worked good!
Now I do not know if it might be Android version problems if they can help me, I'll be grateful.