Inbound from SIP Provider 407 proxy authentication errors

[benf]

Hi, we have had a working system for quite sometime. Today calls started randomly going to the failover trunk. I spoke with the vendor they are getting a 407 proxy authentication required, and then rolling the call over. The issue is I cant re-produce it, but the failover cell phone rang at least 20 times today , and was answered for clients clearly calling our office . We get over 100 calls in a day sometimes, and while the majority worked there definitely is something wrong. Ive tried calling from my cell at least 30 times, trying 10 digit, 11 digit etc to see what it could be but it works. Any ideas what I can look for that would help me pinpoint this? I also re-ran FW checker and it passes no problem.

 

[cobaltit]

https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

Most pertinent questions are going to be if you are using a supported provider and what version of 3CX are you on. But you need to catch this in action, and that's going to be a either verbose logging or wireshark or both.

 

[YiannisH_3CX]

Hi @benf

When the PBX answers calls with 407 proxy authentication required it usually means that you have source identification issues. That means that the PBX cannot match the incoming call to a trunk. Since it was working for sometime then it means something changed either on the PBX side or the providers side. Someone could have messed with the source identification options of the trunk of the number format of the DIDs or perhaps a new trunk was added that somehow interferes with the existing one.
Or the provider is passing some calls to the system that are using a different number format. Normally no matter how you make the call the called number should always be presented with the same format from the provider.
As @cobaltit mentioned you will need to look at the logs or a capture to determine what is causing the issue.

 

[benf]

So the logs weren't even showing an active call coming in. We went through some recent changes, and saw in our change log a change to UDP timeouts from 60 to 30 sec. I put it back to 60, and this seemed to fix the issue. Could that be causing that much of a problem?

For clarification we have several 3cx behind this same device and 3 of them were working intermittently and 3 of them were working perfectly which is why I pushed back on the vendor.

The vendor is siptrunk, and they were helpful up to the point where it was clear on my end, and they even re-checked my trunk config/setup.

Hopefully this solves the issue, and I am going to go back and do a manual override on UDP for the SIP object so it doesn't happen again.