Last night I registered my first Zigbee device to my brand-new HE (a Sylvania Smart+ bulb). It's in a socket in the kitchen wall, about 20 feet from the HE through 2 walls in this old house. It was discovered fine, I can put a tile for it on dashboards, it responds to commands; everything nice and easy!
So today I put a second bulb (identical bulb) in a lamp in the living room—maybe 15 feet from the HE and through only one wall. My belief is that neither of these bulbs should have any range issues.
This second bulb went through the flash each primary color thing when it turned on. Then I went to my devices page on the HE web interface and said discover Zigbee devices (and clicked the button to start discovery). It went through the full 60 seconds and didn't find my new bulb. I tried a few more times, no luck. Finally I went over to the bulb and power-cycled it 5 times, which as I understand it is the factory reset procedure for these bulbs. After that I immediately tried discovery again. No luck.
Any ideas? I do have two more unopened bulbs of this type, I suppose I could try a different one. I haven't tried rebooting the HE, but I don't see that being recommended for problems much. Any way to get more information? I can try pairing it in a lamp in the same room with the hub (I note that that's explicitly recommended against in a number of places, though).