TriggerLinc/SwitchLinc failure

I have my whole home automated with Insteon. Everything is working fine... except I have 3 closets that have TriggerLinc that control the closet lights in them that are SwitchLincs. 1 closet continues to work just fine. 2 of the 3 just stopped working. I've replaced the batteries of course but that made no difference. I can control the SwitchLinc from the Indigo screens to ON and Off so I know they're getting commands. I ordered a brand new TriggerLinc to replace one of the 2 but even replacing it made no difference. It will not link up to the SwitchLinc light switch. Am I doing it correctly? I'm holding the button on the TriggerLinc for 3 seconds until it starts to blink, then I'm holding the SwitchLinc switch up for 10 seconds until the bulb flashes. But the TriggerLinc just continues it flashing at regular intervals and never lincs.

Interference doesn't make any sense to me because out of 50+ devices, these 2 are the only ones that are no longer working.

[jay (support)]

It may be a signal range issue with those two. If you move one of those triggerlincs closer to a dual-band device do they start working?