Re: SRX 1500 cannot use command "set network-management cluster-master"?

Hi,

If you are not using fxp0 then you do not have any active interfaces on the standby firewall. Routing daemon will not be active on the backup node and so you will not be able to reach it. I suggest you use fxp0 to manage both nodes simultaneously. 

Maybe this will help:-

https://www.juniper.net/documentation/en_US/junos-space14.1/platform/topics/task/configuration/junos-space-device-cluster-configuring.html#standalone-to-cluster

Regards,

Anand