Mobile 4G can't send short messages to Unicom 3 G.

Normal online mobile phone users can send and receive short messages to each other. There are several reasons why the mobile phone can't receive SMS or verification code:

1. You can check whether the mailbox is full first. If it is full, please delete some information.

2. If it is still not received after deletion, you can change the machine or card to see if it is a hardware factor;

3. After eliminating the above reasons, you can try to test whether it can be received in other places to see if it is the reason for the weak local signal.

If the above problems do not exist, I suggest you contact Unicom's manual customer service for handling.