When you configure VRRP (Virtual Router Redundancy Protocol), the ping reply on the virtual IP address doesn't work by default. You must configure the parameter accept-data to solve the problem.
Example on EX4300:
set interfaces irb unit 2 family inet address 10.10.1.2/24 vrrp-group 2 virtual-address 10.10.1.1
set interfaces irb unit 2 family inet address 10.10.1.2/24 vrrp-group 2 accept-data