Bluetooth connection

Try this,

Forget/remove watch on your phone in the Bluetooth settings

Uninstall Connect and any other Garmin apps

Pair watch with phone

Install Connect and any other Garmin apps

Thank you.  I just tried that.  No luck.  The Fenix 6s Pro just says initialising until it fails.  The phone never detects it.   No problem if I try to pair my Fenix 5 (which I've removed to make way for the Fenix 6)

Looks like there are some Bluetooth issues with the S20 in general. Have you tried clearing your Bluetooth cache and data? Could be a file left over from the 5 causing issues maybe or not. I noticed if I connected my watch through the Connect app, it would sometimes come up in the Bluetooth device list under a generic name called "watch". It would constantly disconnect and I would have trouble syncing it until I did the above process, which solved all of my Bluetooth issues. 

Than you for the reply.  Yes I've tried that already, and again now since your post.   I'm still not having any luck. 

What firmware version is the watch on? Is it 13.10? Sorry for your luck...

BT v6.11 

Thank you ;(  Yes, this is very frustrating and time consuming. 

I can confirm:

Garmin Firmware 13.10

BT v6.11

I noticed the earlier suggestion to pair the watch with your phone first then with GCM. Perhaps try this way:

Ensure the watch is removed from GCM, then shut GCM down.

Remove/forget (or whatever you do in Android) the watch from Bluetooth settings.

Shut down GCM and shut down the phone. Reboot the watch watch by pressing and holding top left until power down (through the alert setting is active).

Restart your phone and open GCM.

Follow the instructions to pair your watch directly from GCM.

If still not working contact Garmin Support

I have been dealing with this for two days, Fenix 6 pro solar / Blackview 9800 pro phone ( android 9 )
I have tried everything I could fine on the web, or youtube.
What I think I see happening is the Garmin connect software shutting down and not running in the background.
Example : if I lock my phone, Blue tooth stops every time, instantly. If the phone locks itself ( time-out ) the blue tooth goes away soon after.
I am trying one last thing.
I shut off ALL the power saving setting on the phone ( I think it was set to smart saving or something like that }. That I never noticed ( and that has never seemed to affect any other devices car stereos etc. )
After doing that  ( shutting off the power saving settings ) the blue tooth stays on IF the phone locks itself.
 Now If I lock it with the button it still shuts down the blue tooth. But when I unlock it the blue tooth comes back on.

These results are only based on a few hours of experimentation so maybe it will work, maybe not.
I did have some success with a piece of software called Garmin Reconnect , but it was unstable too ( could be from the power saving stuff ) it's a program that also runs in the background.
I might reinstall that now too.
Anyway I don't know if this will help you or not ( i hope it will ).
Best of luck and Happy new year.

Thank you for your help.  I have tried this also, more than once, and again at your suggestion but still not working.  Also, after a full charge yesterday afternoon when it arrived, it ran out of battery and died this morning.  Not sure if it's draining trying to connect to bluetooth or if it's just that faulty.  

In my case, the garmin will connect if I factory reset it, but part of the connection wizard is the initial sync, which stalls.  So eventually I press "skip", but by then the bluetooth has already dropped.  Add to that the battery drain from 100% to switched off in 7 hours, I think the problem is a faulty watch.  I'll wait until Gamin support get back to me before I waste any more of my time on this. 

Good luck with your problem and Happy new year to you also.

Best regards.