Mobile phone arrears. It is the most common situation that the mobile phone is in arrears and can't send text messages. The information center number of the mobile phone is not set correctly. If it does not match the actual information center number of this province, it may not be possible to send short messages. Liyanyun shopkeeper is a powerful intelligent monitoring and viewing software, which can help users to quickly connect the intelligent monitoring equipment installed in the store and view the situation in the store in real time.