Why can't I get any messages?

The first possibility: he is in the field, and the mobile phone can't roam and can't get it. The second possibility: his mobile phone short messages are full, and he must delete some of them to receive them. The third possibility: he set your mobile phone number to the SMS blacklist. You can send it, but he can't receive it. The fourth possibility: too many people send text messages, resulting in the mobile company staff is not in place, not sent in time, but this possibility is very small. But during the Spring Festival, this possibility is very great.