Unable to access Secondary Firewall after Cluster Failover kicks it

Hi,

I recently setup Chassis Cluster Transparent mode on SRX220H2 firewall x2. I have no issue accessing the primary firewall. However I have issue accessing to secondary firewall. I have already setup the IP on irb interface. Understand that the routing engine will only kick in if the primary failed. However I disconnect all the cables on Primary, yet I am still unable to access firewall. Kindly advise.

Primary Firewall IRB: 23.56.45.254/27

Secondary Firewall IRB: 23.56.45.254/27

Default route to 23.56.45.228/27

I have attempted to input backup-router configuration in the primary firewall, but it seems like it does not work at all.

Thanks all!

Regards,

Sean