Driving school said the serial number. Why didn't I get the text message on my mobile phone? What happened?

Network problems, SMS interception or filtering.

1. network problem: the mobile phone network is unstable, which leads to the delay in receiving short messages. You can try to switch to other network environments, such as switching from Wi-Fi to mobile data, or try to receive SMS again after restarting your phone.

2. SMS interception or filtering: Some mobile phone systems or third-party applications will intercept or filter SMS messages, resulting in abnormal reception. You can check the SMS settings to ensure that the SMS function works normally and is not disabled or restricted.