Generic SIP Trunk provider claiming 3CX is not sending password during handshake

[systemed]

We are running a self-hosted 3CX server on a Windows 2019 Server. This setup has been running flawlessly for years. Recently, since Monday (5/8), we have been unable to make outbound calls. Inbound calls and internal ext to ext calls work fine. We are using an unsupported SIP Trunk from a local telecom.

What happens is you dial out (testing with a 3CX app), it sits there for 5-10 seconds as it say "dialing" in the 3CX app, then it says "No answer, call will be ended" followed by a busy signal.

In the logs, I can see our SIP Trunk keeps changing from unregisted to registered every 5 to 10 minutes, and the logs seem to show this started late Friday evening (5/5).

Trunk L:10002(Generic SIP Trunk) has changed status to unregistered. This means that no more calls will pass via this trunk. Please check your network connection and the voip provider or other SIP PBX
and then a second later...
Trunk L:10002(Generic SIP Trunk) has changed status to registered.

Outbound calls in Event Logs generate this:

Call or Registration to 1513###4746@(Ln.10002@Generic SIP Trunk) has failed. 0.0.0.0 replied: 408 Request Timeout; internal

(it really does say 0.0.0.0, I did not edit that, I did add the ### in the numbers).

Getting the SIP Trunk provider to provide support has been very difficult. I finally got on the phone with someone and he explained what they are seeing. I am not at expert in networking so I am going to parphrase what was said. This is coming from one of their sr. techs.

Our 3CX box contacts the SIP Trunk with a request
The SIP Trunk is acknowledging the request
Our 3CX is supposed to then respond with the username and password of the SIP Trunk but "the password field is blank".

I had the SIP Trunk provider generate a new password for the SIP Trunk and I entered it into the 3CX but that has not fixed it.

The firewall checker is green, I've rebooted the server hosting the 3CX box...I have not heard back from the SIP Trunk provider yet. Has anyone ever seen or heard of this happening before?

 

[SweetAction]

Run a packet capture during a registration and see what is actually being sent.

 

[YiannisH_3CX]

Run a packet capture during a registration and see what is actually being sent.

and try switching to a Preferred/Supported provider so you are fully supported and for a better experience.

 

[leejor]

Recently, since Monday (5/8), we have been unable to make outbound calls. Inbound calls and internal ext to ext calls work fine. We are using an unsupported SIP Trunk from a local telecom.

Were any updates done shortly before his all began?
Did your provider say that they made any changes?
Is there other hardware involved...something on-site that was supplied by the provider?

Things don't normally just stop working for "no reason". Since you seem to be getting incoming calls i have to assume that trunk registration is success, so they accept your user and password.
Depending on how many changes have been made since, you might consider doing a restore, to a back-up made before the issue began, or, deleting and re-building the trunk from scratch, after taking another back-up, of course.

Who is the provider....perhaps someone else is also using them and had seen some recent "changes" as well?

 

[SweetAction]

Since you seem to be getting incoming calls i have to assume that trunk registration is success,

Likely it's not a registered trunk for inbound - could just be the telco is sending the calls to an IP/Port and 3CX is what's on the other side. Maybe only outbound needs auth with their setup - this is actually common.

 

[SteveITS]

I had the SIP Trunk provider generate a new password for the SIP Trunk and I entered it into the 3CX but that has not fixed it.

A few years ago we ran into something similar, but it was on an older version of 3CX. And I am pretty sure that what you wrote was what we did...changing the password on their end (and then ours) got it to work even though we agreed we were using the same password.

Also ensure there is no IDS like Snort or other firewall action blocking the connection.

Is DNS working/valid on the 3CX server?

 

[SteveITS]

My brain replayed what I wrote. I don't recall that we were getting the repeated disconnects you describe but we couldn't get it to register without changing the (verified) password.