[asterisk-users] 404 Response to Invite - Should be 401

[Stuart Elvish]

Hi all,

I am currently testing a new version of firmware released by an ATA
vendor and I have come across a strange problem in 1.8.9.0.

Sometimes if I dial immediately after hanging up a previous call (we
used voicemail for our testing as it has "unlimited" capacity)
Asterisk will return a 404 code instead of doing the usual INVITE -
401 - INVITE sequence. The CLI says that the call failed because the
extension was not found in context 'default'. It appears from this (as
the ATA is correctly setup and normally make calls to a different
context) that Asterisk believes the extension is unauthenticated for
some calls and sending them straight to the guest (default) context.

What should I be looking for in the initial invite from the ATA which
will be triggering a 404? Is there something wrong in the SIP header /
body which would be triggering a "safety lock down" of the call? I
have tried to look at the invite packets but I can't see anything that
is incorrect.

On one occasion the sequence was INVITE - 401 - INVITE - 404 but most
commonly it is INVITE - 404.

We have also noticed that sometimes the ATA stops responding to
OPTIONS requests (qualify) whilst this issue is happening and there
may be some other registration issues. Some diagnostics have already
been completed but so far we haven't found anything which points us to
where the issue actually is. We assume it is an ATA related issue.

Any pointers and suggestions greatly appreciated.