Calltoken validation

I’m seeing this error in the CLI:

[2017-03-27 08:42:20] ERROR[1897]: chan_iax2.c:4998 handle_call_token: Call rejected, CallToken Support required. If unexpected, resolve by placing address 127.0.0.1:4573 in the calltokenoptional list or setting user 410002 requirecalltoken=no

But in my iax.conf I have:

calltokenoptional=192.168.67.4/255.255.255.255,127.0.0.1/255.255.255.255

and for the account in question I ahve set:

requirecalltoken=no

I’m running Ast 13.7.2. Is there another setting I need to change, or is the format of the conf setting wrong?