i have on zg1_iax
register => zg1_iax:987@10.100.30.250

and in zg2_iax i have
[general]
port=4569			; port koji ce IAX koristiti
bindaddr=0.0.0.0		; IP adresa koju ce IAX koristiti
disallow=all		; zabranjuje sve audio codece
allow=gsm
allow=alaw			; dozvoljava audio codec
allow=ulaw
trunk=yes

[zg1_iax]			; postavke za ZG1 server
type=friend			; server, peer ili friend 
host=10.100.20.250
context=iax
username=zg1_iax
secret=987

but zg1_iax doesn't register to zg2_iax. 
pbxzg1*CLI> iax2 show registry
Host                  Username    Perceived             Refresh  State
10.100.30.250:4569    zg1_iax     <Unregistered>             60  Rejected

why?