Add aaa to system confdb syntax.
system
.....
aaa
service
*<name>
type
<type>
address
*<ip>
port
<port>
source
<source>
virtual-router
<vr>
forwarding-instance
<fi>
timeout
<seconds>
radius
secret
<secret>
radsec
certificate
<certificate>
tacacs+
secret
<secret>
order
*<name>
security
certificate
<name>