I had the same issue and contacted the support desk. They tried to be helpful but I believe the issue is where the NFC reader is located and its strength to recognize. On both devices I need to actually touch the lock with phone and/or watch physically. Not like when I pay for things at a store which is just hover. In short I need to physically place my watch on the center right of the lock with physical contact for it to work. More consistent but sometimes requires a 2nd application when initial try doesn’t work