Soem years ago, I added both the ME-AGS-N andnME-BMK-N to our ME2012.
I had to upgrade to an ME-ARC control panel to make it all work.
I got similar "no comms" when hooking everything up, and eventually found that it worked best if the control panel is "on one end" and the ME2012 is "on the other end" with all the extra stuff in between. Also important that the connecting cables have 4 wires (many hardware store phone cables only have 2)
I did eventually get the whole system to work, tho I'm looking forward to boondocking more to actually test it in real life.
Iespecially like the BMK, which shows power usage and state of charge and such.
Also, the AGS works MUCH better set to trigger and start the genny based on state of charge rather than voltage.