Check whether the SIM card is a standard nano-SIM card

• Use a standard nano-SIM card.
• Check whether the SIM card is an IoT card. Currently, the watch doesn't support virtual carrier cards or IoT cards.
• Don't use a customized nano-SIM card. Otherwise, the watch may not be able to identify it.

Remove the SIM card from the watch and insert it to a phone to perform a cross-check

Remove the SIM card from the watch, insert it to a phone, and try making calls. If the phone can't make calls either, contact your carrier to check whether the SIM card is out of credit or the call service is abnormal. If not, contact your carrier to change the SIM card. If the phone can make calls, try the following operations.

Enable VoLTE and try again

If VoLTE is not enabled on the watch and the 2G/3G network condition is poor, the watch may not be able to make or receive calls, but mobile data is available.

• Activate the VoLTE service for the watch's SIM card, turn on the VoLTE switch on the watch, and try again. (Method: Go to Settings > Advanced settings > Network & connections and enable VoLTE.)

No signal or no network is displayed on the home screen

• Swipe down from the home screen to check the network signal of the SIM card. If the signal is weak, move to an area with a good signal, such as an outdoor area or a balcony, and then try again.

The contact number you call is incorrect

• Open the HUAWEI FamCare app, touch in the upper right corner and then Contacts, and ensure that the contact number is correctly saved. If the number length is correct or there are invalid characters, the watch will not be able to call the number.
• Try another number (for example, your carrier's customer service hotline). If the watch can make a call, the watch's number may have been put in the blocklist by the other party or the other party's network may be abnormal.