One switch going offline often in the center of 3 gang box

Smartthings support is telling me that I probably can’t put 3 smart switches in one box due to interference or being too close together. I know many of you have the same setup. Thoughts? Ideas?

Support is not that far off. I have 4 of the 3 gangboxes and the middle switches did have weird issues until I changed some from z-wave to zigbee for the middle switches and hardly have any issue since.
The other thing you can do is if you have 3 ways then put the addon switch in the middle.


If the switch has a little antenna on it then: Take 2 to 4 inches of similar wire and add it to the end of the antenna (I would solder and shrink tube it, but a wire nut will work). Route it so you can leave it hang out under the switch cover for a while. If that gets it working then route the extended antenna out of the box by drilling a small hole in the box so it is inside the wall.

Adding length to the antenna can mess with its tune. But if it is blocked (metal box or other switches) extending it can help. You can make your add on extra long (4 inches) and then trim it shorter if need be.

I have an outside lamp post with a zwave relay inside (round metal tube blocked the signal). Extending the antenna up into the glass fixture worked like a charm.

Thanks. However there is no antenna on the GE switch.