Fenix 6S wrist hear rate stopped working

Just the basic suggestions - 

Have you rebooted the watch?

Do the lights of either set of LED's come on at all?  Green or red? 

What firmware are you on, is it the current one? 

Is the current power profile the ultra battery saving one?  Have you tried resetting the power profile to the default one? 

Has the OHR and OX been turned off in the settings? 

If you have the Pulse OX glance enabled, if you open the glance and let it sit for a few seconds does it auto start trying to measure the OX levels? 

Last resort, do a soft reset of the watch, see if they work.  If no, then try a factory reset of the watch and see if they work.   If both of those results in not working then it's pretty unlikely to be software or a configuration issue and most likely to be a hardware issue. 

Since it's two different sets of LED's the odds of both sets all dying at the same time is probably not the highest probability source of the problem.  Could be something further upstream that drives those LED's thought that has failed if it's not just they're turned off through one or more of the possible ways they can be turned off. 

I have tried all of those tips and nothing worked. When I Turn off and on again the Wrist heart rate, the green lights turn on and than off again very quickly. The same happens to the OX. That’s Why I do not know it is hardware problem ir not. Garmin Customer service has not awnsered my Contact yet. I am Waiting and trying to figure out what to do. It is a very expensive Watch and I am very desapoited with my Experience. 

When I Turn off and on again the Wrist heart rate, the green lights turn on and than off again very quickly

My Fenix 6X Pro Solar WHR sensor behaves differently to the previous WHR sensor in my Fenix 5+. The F6 shuts off the green WHR lights pretty quickly if you take it away from your skin, whereas the older 5+ sensor would stay on (or switch back on) if it detected movement.  So the lights turning off quickly after a power on is no surprise (if the watch is not being worn).

Assuming you are now wearing the watch, with the default power profile active, what happens if you go to Menu>Sensors & Accessories>Wrist Heart Rate>Broadcast Heart Rate?  If there's no HR value on screen and if you quickly lift the watch away from your wrist there is no green light visible, then there could well be a hardware issue, especially if you've tried a Master Reset (the 'delete data and reset settings' option here https://www8.garmin.com/manuals/webhelp/fenix6-6ssport/EN-GB/GUID-46551446-AAE7-451C-B857-7D86AD7747EE.html ).  Next step is to contact Garmin Customer Support or just take it back to the shop you bought it from for an exchange/refund.

Thank you, nothing helped... I have tried all those things, and I am waiting for an answer from Garmin... So sad and disappointed. I thought so much before this purchase and I cannot believe this is happening.

I am feeling the same. What was the end result?

Could you please let us know what was the end result? I have the same issue. It worked one and not anymore.

Whats the versions in Settings - System - About - namely for Sensor Hub and WHR

me too same pb after 3-4 years

not reliable watches at all considering price