1. The indicator light 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 detect the SIM card, please confirm that the SIM card has been inserted. If the SIM card has enabled 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 traffic is insufficient or the phone is shut down due to arrears, please replace the SIM card or recharge