Adding SRX cluster into Security Director

Hello

I am having hard time to add SRX cluster into Security Director. I am using SNMPV3. I can add only master SRX. For backup SRX, giving the error 

Junos Space is unable to query the device information through SNMP.  Check the SNMP settings on the device to verify SNMP is not blocked and the SNMP settings specified in Junos Space match the device SNMP settings.

My question is:

1- Backup SRX does not support SNMP bcs even SNMP walk is not working with backup SRX

2- Should I use master IP of cluster to add in Space?