Cannot add "Amazfit Bip" watch as a "trusted device" I've got a ZTE Axon 7 phone, and it generally works fine. I also have an Amazfit "Bip" watch, and I've successfully paired it with the phone via Bluetooth. However, when I try to add the watch as a "trusted device" via the phone "Security" settings, it doesn't work; the phone just immediately tells me that it "Can't add device" even though the watch is turned on and immediately adjacent to the phone. (The watch shows up as a choice in the "trusted device" screen.)

What is it that I need to do to get the phone to pay attention to the watch as a trusted device? I've done this before with the same watch and another Axon 7 phone, and I had no problems then.
I was able to do it; I must have done this in the past and forgotten. From the "Mi Fit" app that goes with the watch, there's an option to set up security pairing. Once that's done, it works via the normal Android screen (the app sends you there).