All of a sudden the switch won't work. Works manually but not using apps or controllers.
I've tried changing the hold, press numbers but nothing.
Consider using what I call 'the Magic Trick'.
Add a 'Virtual Switch' and during the add process, REPLACE the switch in trouble.
(I have a document that describes this in detail).
Once all your 'in Use By' stuff is on the virtual switch, go to the failing switch and push 'remove'. Then, go back to Zigbee Add and start the pair process and with luck the switch will come back right away as once they get excluded from an existing network, they go into Pairing mode automatically. Now 'replace' again the virtual switch, and all the In Use By stuff comes back on the switch again.
DO BACKUP.
Do Screen caps! 
But I JUST went through this on more than one Enbrighten this weekend and it worked perfectly for me.
did you have power surge or outage.. these older ones are notorious for the radio going out during an outage. but the switch would continue to work.
Yes and the power just went out again and the switch is working again.
Gotta love that... 
Glad you had some good luck.