My 5320XM suddenly couldn't send and receive text messages this morning. I changed the information center, but I still can't send and receive.

This problem also happened on my 5320. I turned off the phone, but it didn't work. It is always delayed for retransmission. Today, it's done well. You can try my method. I took out the SM card, stuffed it in, and changed the center number. Path: Information-Settings-SMS sim card information center, delete the number and re-enter, then turn it off and on. Miraculously, we can send it. The center number is your residence. You can download it from Baidu or ask 10086. I hope the landlord can solve the problem.