Vivo mobile phone Unicom card has no signal. What happened?

You can refer to the following methods for troubleshooting:

1. Confirm whether to use third-party magnetic attraction or metal fittings.

Please check whether metal protective shell, magnetic protective shell, magnetic bracket and other accessories are used. Metal and magnetic materials can easily interfere with signal reception. It is recommended to remove the parts for inspection.

2. Confirm whether the current environment covers the carrier network.

If you are in a closed indoor environment (such as basement, elevator, etc. ), the cell phone signal may be blocked, resulting in poor signal, you can go to the outdoor environment to check. If you are in a remote area and the signal may be poor, you can use the cell phone signal of the same operator network around you to determine whether it is the cause of network coverage.

3. Check the SIM card and verify the cross card replacement.

Observe whether there is dirt or oxidation on the metal surface of SIM card, and check it after cleaning. If you use a tailored SIM card, it is recommended to replace it with a standard SIM card. Install the SIM card to other devices, or install other SIM cards to the mobile phone for comparative test to determine whether the SIM card is faulty. If it is due to the SIM card, it is recommended to reissue the card in the operator's business hall.

4. Dual telecom cards need to use VoLTE network.

If two telecom cards are used at the same time, the secondary card (non-data card) needs to open the VoLTE service and be within the coverage of the VoLTE network before registering the network.

5. Reset network settings

Do a good job of backing up data such as WiFi, enter Settings-System Management-Backup and Reset-Reset Network Settings-Select the corresponding SIM card-Reset Settings, and then use it to check.

Note: Resetting the network settings will clear the connection records such as WLAN, mobile data network and Bluetooth; Dual cards need to select the corresponding SIM card.

6. Restore all settings

Do a good job of data backup, go to Settings-System Management/More Settings-Backup and Reset-Restore all settings, and follow the onscreen instructions.

Note: Restoring all settings will not delete any software and files, but only restore all settings. Please ensure that the use of the software will not be affected before operation.

7, service center testing

If the above methods fail to help the recovery, it needs to be detected and handled by the customer service center (customer service center address: go to vivo official website /vivo Mall APP-My service outlets/after-sales outlets-select provinces and cities to inquire about the customer service center address).