Iax trunk not working, cant receive calls from another pbx

Asterisk Asterisk General
1

//ASTERISK 1.8

[Jul 19 11:39:20] WARNING[7565]: chan_sip.c:5441 create_addr: Purely numeric hostname (701), and not a peer–rejecting!
[Jul 19 11:39:20] WARNING[7565]: app_dial.c:2274 dial_exec_full: Unable to cr eate channel of type ‘SIP’ (cause 20 - Unknown)
== Everyone is busy/congested at this time (1:0/0/1)
– Executing [701@internas:2] Hangup(“SIP/502-00000005”, “”) in new stack
== Spawn extension (internas, 701, 2) exited non-zero on ‘SIP/502-00000005’

2

Asterisk 1.8 is past end of life.

Your log shows an incoming SIP call failing to make an outgoing SIP call. There is no IAX, on either side.

3

//PBX1
localhost*CLI> iax2 show peers
Name/Username Host Mask Port Status
demo/asterisk 216.207.245.47 (S) 255.255.255.255 4569 Unmonitored
troncal/bxx1 192.168.38.170 (S) 255.255.255.255 4569 OK (6 ms)
2 iax2 peers [1 online, 0 offline, 1 unmonitored]

//PBX2
localhost*CLI> iax2 show peers
Name/Username Host Mask Port Status
demorisk 216.207.245.47 (S) 255.255.255.255 4569 Unmonitored
troncal/upbx1 192.168.38.171 (S) 255.255.255.255 4569 OK (5 ms)
2 iax2 peers [1 online, 0 offline, 1 unmonitored]

4

You would need to provide console of an actual attempt using IAX2. As @david551 stated - the small amount you provided only shows a SIP call attempt that failed.