I have my app loaded in FogD. FogD does have connectivity to the 1835 because it will load the device log from within FogD (Devices. > select device > View Device Logs). When trying to push the image to the 2 IR1835 I have, this is the error I receive in FogD:
Incompatibility Cause
The device capability is not discovered successfully. Refresh this device again and install the app.

Also refreshing the device from within FogD, this is the details next to 'Last Heard':
{"errorcode": -1, "description": "Layer registry is not available", "message": "Layer registry is not available"}

ASAP-SE-02-04-IR1835#show app-hosting list
No App found
router#show iox-service
IOx Infrastructure Summary:
---------------------------
IOx service (CAF) : Running
IOx service (HA) : Not Supported
IOx service (IOxman) : Running
IOx service (Sec storage) : Running
Libvirtd 5.5.0 : Running
Dockerd v19.03.13-ce : Running
router#