1. Do not use the standard Nano-SIM card. Don't use a non-standard SIM card or cut the card yourself, because cutting the card will easily make the SIM card unrecognizable or damage the phone. I suggest you go to the business hall and change to a standard SIM card.

2. Please confirm whether the SIM card is placed correctly and whether the gap of the SIM card corresponds to the card slot. Please refer to the attached product manual for details.

3. Please confirm whether the surface of SIM card is dirty. If so, you can wipe the surface of the chip with alcohol, or replace it with a new standard SIM card in the business hall. SIM card is used for a long time, and the metal surface is easily oxidized, which leads to a high probability of not knowing the card. I suggest you go to the business hall and get a new standard SIM card.

Please don't insert or pull out the SIM card when it is open. If you insert the SIM card in the power-on state, please restart the phone.

If the above methods fail to solve your problem, please back up your data in advance and go to the nearby Huawei Customer Service Center for maintenance.