Make sure the Nano SIM card is,
***a valid Nano SIM card;
***must applied the Mobile Internet Data service, which is
provided by the Telecom provider;
***must applied the incoming phone call number displaying
service, which is provided by the Telecom provider.
How to insert the Nano SIM card into the SIM card slot?
1) Power OFF the smart watch
2) Second, there is a small screwdriver provided in the gift box,
use the small screwdriver to take off the screws from the shell of
SIM Card Slot.
3) Third, take off the shell, and then insert the Nano SIM card
into the SIM card slot. Follow below sketch.
You can hear a tiny sound once the Nano SIM card has been
inserted into the SIM card slot and into the right position.
To take the Nano SIM card out from the card slot, push it in
towards inside, to let the Nano SIM card bounce off the slot.