Android phone stopped seeing the device's bluetooth?

Question

Bluetooth

Hello!
All evening I set up the Xiaomi mi band 1s fitness tracker.
I messed up, but got it set up. And literally in a few minutes the phone stopped seeing any bluetooth devices. At home, two bracelets, iphone, ipad, everyone sees each other perfectly, except for my Hindu asshole (micromax a106).
Reboots, turning on / on bluetooth do not solve the problem, the only interesting point is that if you go into the bluetooth settings on the iphone, then my micromax sees it right there (probably because the iphone itself starts to scan the nearest devices), while the iphone, in turn, does not see micromax.
Could not the bluetooth just die on the phone?