How is it that mobile phones always receive some unknown calls?

If the caller ID of the mobile phone is unknown, there may be several reasons:

1. If this happens to individual mobile phones:

1). Maybe the other party has turned on a function similar to hiding numbers.

2). The other party may make a phone call through unconventional channels, such as the Internet.

2. If this phenomenon occurs on all mobile phones:

1). The caller ID function is not enabled on the mobile phone. Please ask the operator if caller ID is enabled.

2). Try to replace another SIM card.

3). Check whether the mobile phone has firmware/system push notification. If yes, please upgrade your phone to the latest version.

4). If not, please back up the data in your mobile phone (such as address book, multimedia files, etc.). ) and restore the phone to the factory settings.

If the problem still exists, it is recommended that you take the purchase invoice and three-guarantee certificate to the nearest after-sales service center for testing.