Syncing with Garmin Explore stopped working - SOLVED

Hi,

I realized that my Fenix 6 Sapphire stopped syncing with Garmin Explore app for iOS. First I thought it is problem with my app but my GPSMAP 66i is syncing with this app without any problem. 
Until now I did: restart watch and phone, remove watch from BT in phone, from devices in Garmin Explore and Garmin Connect Mobile. Connected and paired everything from the beginning and it not solved my problem. Syncing with Garmin Connect Mobile is all the time working OK. When I trying to sync with Garmin Explore it shows that it is paired with watch then syncing taking ~45 second and shows red text: "Sync failed: and time".
I am using iPhone 12 with latest iOS, Garmin Explore and Garmin Connect Mobile are latest version too.

Can anybody have idea what I can do to get back my syncing with Garmin Explore app?

Best
Arek