This issue has been resolved(06/14/2016)
Overview of the Issue
There may be cases that the communication with virtual IP addresses is unavailable between the Load Balancers (NetScaler VPX) configured VRRP. In this case, the failover to backup Load Balancers (NetScaler VPX) does not occur, or the communication to master Load Balancers (NetScaler VPX) is not recovered automatically. Customers need to reboot the master Load Balancers (NetScaler VPX) via Enterprise Cloud Customer Portal to recover the communication.
Please refer to Service Description of Load Balancer (NetScaler VPX) for detail regarding configuration of VRRP.
Solution
Customers need to reboot the master Load Balancers (NetScaler VPX) via Enterprise Cloud Customer Portal to recover the communication.