How to debug failing apk ==> host connection?

I have a VPS on the web successfully running my app, behind Nginx as, for example,

Locally, I have a virtual machine running Kit Kat, and I can monitor successful mobile browser execution of my app with chrome:inspect on the development virtual machine.

I push the app’s APK into the KitKat VM using ADB, and install and run apparently successfully. However, unfortunately, in the places where non-static elements should appear, I get only


Using the network tab, in chrome:inspect, I see that it’s trying unsuccessfully to GET the correct URL:

The initiator code of the failing GET is ad596fc......a58ec.js?meteor_js_resource=true:89
Line 89 ends with :

 (Package["ddp-client"] = {}, {
        DDP: h,
        LivedataTest: v

I can see the <head> section of the main page contains a call to load that script, but there are additional calls to http://localhost/:

 <script type="text/javascript" src="/ad596fc......a58ec.js?meteor_js_resource=true"></script>
 <script src="http://localhost:12896/cordova_plugins.js"></script>

I have had all this working previously, but I’ve rearranged my build process in a number of ways, and now discover that this part is broken.

My questions:

  1. Is there, possibly, a well known reason why this might be occurring?
  2. Is it possible that the APK bundle is missing those localhost script files? How could I check?
  3. In the code of line 89 there are many statements such as h.ConnectionError("DDP heartbeat timed out.... and debug("Closed transport:...", but I see no such error messages in the browser console. Where else might I find such error logs if indeed there are some somewhere?
  4. What more can I do to track down the root cause?