ISY994i setup with typical Insteon Dual Band On/Off Modules, Switch Lincs, and RF band battery powered motion sensor, door switches and leak sensors. Noticed all battery sensors except one door switch no longer communicate. Cannot get any of the previously operating battery sensors to re-link. Get the typical can't determine Insteon engine error. Yes, putting the sensors in link mode by holding the button down for 3 secs and get the flashing light. Have to delete the old references of a sensor to get the 994 to even attempt to link. Yes, attempting to link a sensor within one foot of the PLM. Seems the PLM RF radio is still working one door sensor still communicates. All the dual band end devices continue to work as always. Tried different PLM same result. Don't have a spare 994i.

Anyone seen this before? Ready to scrap the 994i and the insteon devices and move on to HA and the newer WIFI mesh based devices.

Thanks to all.

How old is the PLM? If you don't know, there's a little white stick on the back with 4 digits, what are they?

Have you had a major power event, eg brown out, black out, nearby lighten strike?

Did you un-plug, wait 10 seconds and re-plug the PLM and retest?