Garmin HRM Pro Plus

Hello,

I just bought Garmin HRM Pro Plus.

After connecting it to my Fenix 7 Pro it stays connected only while I am in Sensors and Accessories Settings tab on watch.

When I am going back to watch display my HRM disconnects after few seconds.

Connection type ANT+ and shows that battery is OK. Tried to take it out and keep for a while but that's not helped.

Tried to connect and disconnect it in app or BT, nothing chanmged.

Any ideas?

Thanks