Android Notification With Photo - websocket_api Error

Looking for some insight as I’m having some issues receiving a photo with notify.mobile_app. No problems to receive a message, and no issues with actionable notifications either, just no photos.

In Developer Tools > Services: I’m trying to send an image to my HA Android app, however I receive the following error: homeassistant.components.websocket_api.http.connection.123456789 each time.

The Call Service I’m trying is:

image: https://some random public image from google - nothing special

So what gives?

My Set-Up:

Lattepanda
Windows 10
VirtualBox
Ubuntu
Hassio

I can’t enable the front-end in my Profile…its grey (Backend-selected).

Doing a little sniffing around apparently front-end is supposed to be enabled by default, but not for moi. The websocket_api has something to do with this when a profile is running on the back-end and api needs to be enabled in the confi.yaml file. I just can’t figure out how,what,why I should be changing it to send a photo to my mobile.

This would seem to be a configuration issue. However I’m not sure. My HA set-up is minimal. No real add-ons or modifications to my config.ymal at all. Any insight would be appreciated.

Many thanks.