Mi band 4 don't give heart rate

App don’t get heart rate from my Mi band 4.
I can see that band at the list of BT devices, but I don’t get heart rate: near the red heart icon I can see “-” only.

The band has to be paired with his setting app “zepp life” to work and sync time.

How to resolve problem?

I partially solved the problem: in the band settings in “Zepp life” I turned on “heart rate monitoring” and “frequency 1 minute”. Now in the sport Tracker in the band settings, it shows the heart rate every 1 minute. But that kind of information is not practical - I would like a voice message with the heart rate value every 1 km during training, can I set it like that?

I would need to add this.