Cell phones always delay messages or can't receive them. What happened?

Unicom number cannot receive SMS for the following reasons:

1, you can first check whether the mobile phone has blocked the SMS receiving function;

2. If it is not blocked, please check whether the mailbox is full. If yes, please delete some information.

3. If you still can't get it after deleting it, you can change the machine or card to see if it is a hardware factor.

4. Try to receive it in other places to see if it is the reason for the weak local signal;

If the above problem does not exist, please contact the local Unicom customer service to handle this problem.