Cannot pair with mobile app or Garmin Express (F5)

Hi,

I've downgraded to firmware 13.3 from 20.x.

With new software battery drain was huge even with watch settings reseted to defaults.

When I tried to pair again, the app stops at Connect Device button.

I removed watch from account, I cleared app data, watch hard and soft reset, restart phone...

Got no more ideas...

Any auggestoons?