Venstar T1800 not communicating

[dvs]

I have an ISY99i on version v.3.2.6 with 2 Venstar T1800 thermostats with the integrated Insteon module. I can communicate with the upstairs unit fine but the downstairs unit gives the error "can not communicate with downstairs T1800 (14.65.2D). Both of these units were working a month ago so I swapped locations of the units and did the factory reset but the 14.65.2D device still will not communicate. I swapped all the dual-band access point locations around and there is no change in the ability to communicate with 14.65.2D or any other device on my network. I'm stuck and don't know what to try next.

[bsobel]

If I followed you moved the module from the 'downstairs' to the working 'upstairs' location and the issue changed (upstairs no longer worked and downstairs started to work). If so sounds like you have good COM to both places, the unitself may be bad (I've had 2 early ones go out and recently had the thermostat itself go out [but the insteon unit was fine]).