127.0.0.1 refused to connect on Android

FNC TMS FNC Cloud Pack
1

I'm testing a mobile version of my app with FNC Cloud Pack. It works on my iPad (and on Windows) but fails with "This site can't be reached" and ERR_CONNECTION_REFUSED on my Android phone.

2

This issue goes away after adding the port 127.0.0.1:8888 to the callback URL.