I opened a Unicom mobile phone card, why can't I get a text message?

The processing method of mobile phone unable to send SMS is as follows: 1. I suggest you change your mobile phone and see if you can send and receive short messages. 2. If you can send and receive short messages, I suggest you plug the card back into your mobile phone and send yourself a short message to see if you can receive it. 3. If not, I suggest you check whether it is a sim card problem. 4. Check whether the number of SMS center is set correctly. 5. Bring the mobile phone card to the local business hall for testing or replacement.