Wrong HRM data Hiking and Cross-country skiing

Hi

I have wrong, very low HR data from my Fenix6 with hiking or doing cross-country skiing. Hiking is without poles and cross-country is ofcourse with poles.

Have tried to update the watch, clean, change wearing positions, tighen/loosen it but I get much of my workouts around 110bmp while the actual figure is way higher.

How do I fix this?