The meaning of unregistered terminal is:
1. Your POS machine has been connected to the background of the order receiving system, and the connectivity is normal.
2, indicating that the system you connect to is not configured with the merchant number and terminal number you use. What you should do is: 1, check your communication parameter Settings, including TPDU, to see if it is connected to the wrong system. 2, go to the background system to check whether this merchant and terminal have been configured. (If you can't see it, contact the person who installed it to check it) I hope it can help you.