Mobile cards can only send short messages in Jiangsu and Hunan.

If other people's cards are ok, but only yours is not, I suggest you try changing your mobile phone to change your card (put your card on another mobile phone and other cards on your mobile phone). If you can send other cards on your mobile phone, it's a card problem. If it can't be sent, it's a cell phone problem. If there is a card problem, just go to the business hall and reissue it.