Step counter / HR sensor stopped working!? Garmin Instinct

Hello everybody.

I've been using my Garmin Instinct since 2020 without any issue.

Today, for no specific reason, the step counter together with the HR sensor stopped working, while the smartwatch keeps working.

Does anybody have an idea of what could be the problem? It seems also that the light behind the watch is always off.

Thank you in advance and sorry for not my perfect english