Local terminals or remote terminals cannot call each other through IP addresses. Which of the following statements is incorrect?

Local terminals or remote terminals cannot call each other through IP addresses. Which of the following statements is incorrect?
A . The local end is in a private network, the remote end is in a public network or another private network, and the NAT parameters are not set correctly.
B . Failure to register GK locally or remotely
C . Local or remote network disconnection
D . GK registered locally or remotely is not allowed to call through IP address

Answer: B