Scenario: While performing a disaster recovery test, a Citrix Administrator decides to failover the Citrix ADC high availability (HA) pair appliances. The administrator notices that the failover is NOT working as expected, and the secondary Citrix ADC is NOT taking over as primary. The administrator suspects that networking issues may be causing the failure.
What could be the cause of this issue?
If HA monitoring is enabled on an interface of the secondary node that shows as ENABLED, DOWN, it causes the high availability failover to not function properly. When the interface monitored for high availability is down, it can prevent the secondary Citrix ADC from assuming the primary role. Ensuring that monitored interfaces are operational is crucial for the failover mechanisms to work correctly. Thus, networking issues on the secondary node's monitored interfaces could indeed be the cause of this issue.
I think A , REFERENCE https://support.citrix.com/article/CTX204685/secondary-node-shows-down-in-netscaler-high-availability
https://support.citrix.com/article/CTX109013/troubleshooting-netscaler-high-availability-ha-issues