Unable to set up Dimmer

[BrightRedFish]

Hi, here's a question from a newbie. I have several dimmers I have successfully set up in the Lutron app, but I have one that I can't seem to set up. When I press the bottom button on the dimmer for ten seconds, the LEDs on the dimmer blink rapidly, but the Lutron app never goes to the next page to categorize the dimmer. I have installed a lamp dimmer, so I have a range extender set up, and it shows up in the app. The dimmer is about twelve feet or so from the lamp dimmer. I think the dimmer is getting a signal from the range extender, because the LEDs continue blinking until I back out of the app. When I hit the back button on my phone, the app indicates "finishing setup," but the dimmer is not shown. At that point, the LEDs on the dimmer stop blinking. Any ideas?

[SDR-Mike]

Try a factory default on the switch that isn't responding. It may think it is part of the QC system back at the mothership, and didn't get defaulted out the door. Happens occasionally.

Tap the off four-five times in very rapid fashion. The faster the better.
Hold Off at end of taps until the dimmer/switch looks like the lights are flashing.
Release the Off and immediately repeat the four/five taps again, this time just let it go. Do not hold after the second set.
Should see the lights on the dimmer flash a bit differently, then go "fuzzy" as the dimmer resets itself

Try and add about 30-60 seconds later.