My calling card is Guangdong Unicom 3g, package B, but I can't send short messages when I leave Guangdong, but I can send them again when I enter Guangdong.

You may need to set the SMS center number in your mobile phone to use it. It is suggested that you can set the number of the SMS center.

The SMS center number of Guangdong Unicom number is as follows:

1. The number of SMS service centers in Guangzhou, Zhuhai, Shaoguan, Huizhou, Zhongshan, Jiangmen, Zhanjiang, Maoming, Zhaoqing, Qingyuan, Yunfu, Foshan and Yangjiang is+8613010200500;

2. The telephone numbers of SMS service centers in Shenzhen, Huizhou, Shantou, Chaozhou, Heyuan, Meizhou, Shanwei, Jieyang and Dongguan are +86 130 1088500.

Setting method:

After you choose to enter the "SMS" menu of your mobile phone, enter the SMS center number in the "SMS center number" column, and press the OK key. This number will be stored on your card, and you can use SMS and various services directly without resetting in the future.