1. The indicator is always red, the signal is too weak, please adjust the position and direction of the device; 2. The red and blue indicators flash alternately, the device does not recognize the SIM card, please confirm that the SIM card has been inserted. If the SIM card has activated the PIN, you need to insert the SIM card into the mobile phone to disable the PIN code, and then try again after inserting the device; 3. The red and blue lights flash alternately and slowly, the data traffic is insufficient or the phone is turned off due to arrears, please replace the SIM card or recharge it. Translated with www.DeepL.com/Translator (free version) 

The red light of the indicator is always on, the signal is too weak, please adjust the position and direction of the device; The red and blue indicator light is flashing fast alternately, the device has not detected the SIM card, please confirm that the SIM card is inserted. If the SIM card has PIN turned on, you need to insert the SIM card into the phone to disable the PIN code first and retry after inserting the device; red and blue lights flashing alternately slowly, insufficient traffic or unpaid stop, please replace the SIM card or top up; 

Yes, it comes with a SIM card and 100M of free traffic for the first setup 

Yes, it comes with a sim card. 

Hello, unfortunately no, you cannot insert a SIM card in this smartwatch.