What is the reason why Xiaomi mobile phone failed to send verification code?

There are various reasons why Xiaomi's mobile phone failed to send verification code. What is one? One is that the mobile phone itself has some problems, and the memory is too large to send this short message. The first and second points are that the temperature is too high, which limits the sending. As we all know, this one of Xiaomi is easy to get hot, and it is very easy. After the temperature is too high, it will restrict many functions, including sending a short message and receiving a verification code. The second point, the third point, is that when its system is updated and maintained, this actual certificate number is maintained, and you can't send and receive the verification code because of the maintenance, no matter which method? In fact, if you really want to solve it, you still have to ask the customer service for a personal consultation to solve it, because in each case, his possible phenomenon is different. In fact,