Why do some schools receive text messages and others fail to receive signals?

This problem is very complicated. There are three operators in China Mobile Unicom, and their opening methods are different. First, check whether the number of the backstage newspaper is consistent with your mobile phone number. If there is a mistake, it can't be opened.

If there is nothing wrong with the number, check whether there is something wrong with the mobile phone. There are single-card phones and dual-card phones.

If the single-card mobile phone can't receive short messages normally, 99% is caused by the short message firewall, then deleting the firewall and blacklist is basically enough, and the remaining 1% may be the problem that the sim card is full of viruses or short messages.

If it is a dual-card mobile phone, the problem is complicated. Some mobile phones have two cards, and some mobile phones can receive short messages normally by taking out one card. Some dual-card mobile phones can't receive short messages even with only one card. Some dual-card mobile phones can receive short messages at first, then suddenly they can't, and then they can't receive short messages anymore.