The FaxMaker unknown error 3 is very vague in its description, and this article will provide more information about it as well as things to do to resolve the issue causing the error.
The unknown error 3 can happen when using other fax devices but is most common in Brooktrout devices. The unknown error 3 generally occurs during the setup section of the fax, when CNG and CED tones should be exchanged by the fax endpoints. Listed below, by device type, are the description of why the error is given and things to do to resolve the issue. This is not usually seen with ISDN devices.
When analog devices are connected to a phone system, we can see these errors. They occur when trying to set up the call and from ticket reviews, we generally see the phone system rejecting the call.
Verifying the phone system being used is set up and has sufficient resources to handle the fax call volume is the best first step for this error. If everything appears to be set up properly in the phone system, then open a ticket with GFI Support and upload the FaxMaker troubleshooter logging.
Fax over IP
When using FoIP, it is very similar to analog lines in that the call setup is not being completed. When using SIP the 3-way handshake is not being completed as well as when using H.323 where the OLC (open logical channel) is not being completed. Troubleshooting the reasons why this setup is not being completed is the next step.
The easiest way to review the setup signaling is with a Wireshark capture. Start by capturing a call with Wireshark, the Using Wireshark article gives instructions for this. Once the capture is available to review, follow the steps below to review the capture:
- Select telephony from the top menu bar and then select VoIP calls.
- From the VoIP Calls dialogue box, select the call you would like to analyze. If you are unsure which to analyze, select one of the rejected calls in the state column.
On the left, in the screenshot above, we see the call selection. Then elect flow sequence to see the signaling of the call. On the right, we see the call setup start, but no logical channels being opened. This would cause an unknown error 3. This was also a received fax where the fax server is on the right and responded to the signaling sent by the PBX but no responses came from the PBX after, so the call was released. This example used H.323 and below will show a SIP example.
Follow steps one and two above for the SIP capture you will see something similar to the example below. In this example, the FaxMaker server is on the left and is sending a fax. We see the invite go out but the PBX responds with an internal server error and the call is stopped.
Reviewing the packet captures gives a direction to start troubleshooting, for instance, to see why the PBX responded with the internal server error and correct it.
Not every unknown error 3 will be due to an internal server error, we could get one of many failure responses back from the PBX. The cause of the rejection is usually a configuration setting mismatch between the PBX and the FaxMaker server. The article Customizing the CLIP and TSID Values of Outbound Faxes discusses changing the CLIP value for the outbound fax and if the SIP response is a 404, the PBX could be looking for a specific DID value in the from field of the invite. This article also explains the variations of setting the CLIP value as well as when to use what settings.