[Asterisk-Users] dual servers

[Altus Snyman]

Good day all
I'm trying to configure 2 asterisk servers running sip to connect with
each other with iax so both sip extensions can dial each other
I'm using this webpage but I'm a bit stuck
each time I try to dial the other server's sip extension it says trying
and then just gives a busy tone.In asterisk it says it could not create
aix channel and that all is busy at the moment
Can someone please advice or maybe there is a something I'm bot
enabling?
Thanks
Enjoy the weekend
Altus