First of all make sure that the priority on both members are different by no more than 20, but in your case 10. Advise use prio delta of 10 and prio of 195 and 200, with both numbers ending in a 0 it is not always clear which of the 2 should be master.
Check the state on both members with cphaprob stat and see if both members show active/active.
In Dashboard/SmartConsole have you set the clustering method to VRRP? In the global settings also look for the allow VRRP setting to be allowed before first.
For a test type set vrrp monitor-firewall off and see what happens.
Last thing to check is to see for sure that the switches you have connected both FW's to, are set to allow multicast traffic.
Regards, Maarten