To ensure that traffic transmission is not affected by server or link failures, the administrator has configured the health check of the link, but after the configuration is completed, it is found that the status of the health check is still Down. What are the possible reasons? (Multiple choice)

To ensure that traffic transmission is not affected by server or link failures, the administrator has configured the health check of the link, but after the configuration is completed, it is found that the status of the health check is still Down. What are the possible reasons? (Multiple choice)
A . The TRUE end device has not released the corresponding protocol and port
B . The security policy does not allow traffic
C . The link for the health check fails
D . The health check is not called on the interface

Answer: ABC