[asterisk-users] Can someone please help with this sip2sip pjsip_wizard "no matching endpoint" issue?

[Jonathan H]

Using pjsip 2.7.2 on Asterisk 15.5
Really struggling to make sense of translating these old 1.8 SIP
instructions into a neat pjsip_wizard conf suitable for 2018
http://wiki.sip2sip.info/projects/sip2sip/wiki/SipDevicesAsterisk#Version-18

In pjsip_wizard.conf, I have the following, which seems to get me
registered, and it responds to an incoming call, but I always get
this:

[Jul 28 18:32:29] NOTICE[22492]: res_pjsip/pjsip_distributor.c:659
log_failed_request: Request 'INVITE' from '"demo"
<sip:myusername at sip2sip.info>' failed for 'x.x.x.x:5060' (callid:
5fa139428fef42d9bd0cd4063e10b047) - No matching endpoint found

here's what I have in pjsip_wizard.conf

    [sip2sip]
    type = wizard
    sends_auth = yes
    accepts_registrations = yes
    transport = simpletrans
    outound_auth/username = myusername at sip2sip.info
    outound_auth/password = password
    remote_hosts = 81.23.228.129,85.17.186.7,81.23.228.150,sip2sip.info
    endpoint/allow = alaw
    endpoint/context = fromsip2sip
    aor/max_contacts = 3
    registration/contact_user = myusername
    outbound_proxy = proxy.sipthor.net
    endpoint/language=en_GB

in pjsip.conf

    [simpletrans]
    type = transport
    protocol = UDP
    bind = 0.0.0.0

    [acl]
    type = acl
    deny = 0.0.0.0/0.0.0.0
   ; next 3 are for sip2sip
   permit = 81.23.228.129
   permit = 85.17.186.7
   permit = 81.23.228.150

in extensions.conf, I've got a bit OTT and covered every possible base
to match an endpoint! Every single item in the "to" or "from" header
is accounted for somewhere, so why can't it find this endpoint?
Would be really grateful. Thanks.

extensions.conf

    [fromsip2sip]
    exten => _.,1,Verbose(answered)

    [myusername]
    exten => _.,1,Verbose(answered)

    [myusername at sip2sip.info]
    exten => _.,1,Verbose(answered)

    [demo]
    exten => _.,1,Verbose(answered)