Heart rate drops out

My heart rate drops out when riding my bike or running on the trendmill.

How can I fix this?

I test the heartrate device and it not the heart rate monitor Because the trendmill does not drop out and after drop out after , I used the myzone app and there was no drop outs.

Nokia G10 phone with android 12

Need more detail reference the make / model.

How are you connecting it?

Myzone z3

Connecting via the Bluetooth

It was working before the update

Nokia G10 anoroid12