No need to open a case.. I already did and here's what Cisco told me. Error 0:
The error 0 usually means that something failed in the authentication
process. When the phone tries to check credentials, it post them to the
authentication URL. If the URL is bad, unreachable, returns an error, or
even no response, the 0 seems to show itself.
The order in which the authentication occurs is as follows.
- Post XML to phone.
- Phone post credentials to the Authentication URL
- Authentication URL response with Clear Text Messages (Authorized,
Un-Authorized, Error)
- The phone then responds to the Post with a CiscoIPPhoneResponse or
CiscoIPPhoneError as appropriate.
If the phone doesn't make a request to the authentication URL, make sure
it has a URL. If it has a host name, check for DNS messaging in the
trace. Also power cycling the phone will clear any cached credentials or
DNS resolutions. The phone will cache credentials when they are valid
and only recheck on mismatch with a subsequent request or timeout of the
cache entry.
Error 6:
This occur when you have to push more than
once to get the event to take. It is typically because the socket on the
first attempt was being closed by the push agent before the phone
completely finished the push request. The phone bails out of the
processing logic and returns error 6.
The work around for this is
The phone has to be power-cycle to recover from this condition
I kept getting a 0 despite all that but never found time to set up a sniffing session (not so easy across vlans with the hardware I have) and I ended up upgrading the phones and right now things appear to be working so I'll await the next time something fails before setting up a sniffer session and reopening the case.
