Networking issues w/ Android App: trouble connecting to server

I’ve been stumped on a networking issue. I have two devices on which the Android OpenHAB client connects just fine, and two devices where it just “spins” and is unable to connect. All devices are given a 10.20 private IP address, but the openhab server is inside a wifi router (another private LAN) that’s in a 192.168. The router is port forwarding correctly, and the app on all four devices is pointed to the router’s external IP address. So it looks like this:

Wifi Network for phone/tablets devices are in:

Within this network, a router w/ IP and openhab server on private LAN inside this router:
Connections to are port forwarded to

When all the phones/tablets are inside the 192.168, and pointed to server, the openhab app works for all devices.

When the phones/tablets are outside of that 192.168 LAN, and use the URL, only two of the devices apps connect; the other two do not. For the tablets that don’t connect, I’ve tried putting the URL on both local and remote fields, either alone or both, so all combinations. And I’ve made sure all the settings are the same

App Setting “local” or “remote” URL:

Working Devices:

  1. Nexus 6, running Android 7.0, Habdroid
  2. Moto E, running Android 5.1, Habdroid

Non-connecting Devices:

  1. Samsung Tab, Android 4.4.2, Habdroid
  2. Samsung Tab, Android 5.1.1, Habdroid

I want to emphasize that if I just open up a browser and to go, that works on all four devices, even on the two devices where the mobile app has trouble connecting. Weird?

Is there something tricky to this? I’ve made sure the openhab settings on the non-connecting devices are exactly the same as the connected devices.

I had a similar issue in that I could not connect locally via the app but through a web browser there was no issue. Also through the app I could connect to since I use the openHAB cloud addon. Finally I realized I wasn’t using SSl and saw the clerical error that I was using HTTPS instead of HTTP. Maybe not your issue but might help someone else.

You could try re-installing HABDroid…

Something similar happened here: