Common fax errors

This page lists the most common fax error messages along with the likely reason and troubleshooting steps for resolution. If these steps don’t resolve your issue, open a support request and include the Fax SID with the error.

Common errors

Connection Failed

Meaning: There was no receiver on the other end of the call to connect to.

Reason: The destination is not confirmed to receive facsimile transactions.

Troubleshooting steps:

• Retry.
• Contact the owner of the destination number to confirm compatibility and connectivity.

Disconnected after permitted retries

Meaning: The fax service attempted to send the same message multiple times unsuccessfully. This may be due to a call clarity issue.

Reason: Poor network conditions.

Troubleshooting steps:

• Retry.
• If network conditions persist, contact SignalWire Support to reach out to our carrier peer.

Document generation error

Meaning: There was an error while generating the document. This could be due to the file being deleted before sending.

Reason: Internal Service Error.

Troubleshooting steps:

• Retry.
• If the issue persists, contact SignalWire support.

Document loading error

Meaning: The fax service attempted to generate the message to send but a document was missing.

Reason: Internal Service Error.

Troubleshooting steps:

• Retry.
• If the issue persists, contact SignalWire support.

Failed to train with any of the compatible modems

Meaning: A remote fax machine was detected, but the sending and receiving modems could not establish communication.

Reason: Connectivity issues.

Troubleshooting steps:

• Retry.
• If the issue persists, contact SignalWire support.

Far end cannot receive at the resolution of the image

Meaning: The remote fax machine does not support receiving faxes sent by our service.

Reason: Quality is too high.

Troubleshooting steps:

• Try lowering quality (resolution is known as “quality” in Programmable Fax).

Fax transmission not established

Meaning: We could not detect a remote fax machine. This could be due to there being no fax machine on the receiving end or a lack of call clarity.

Reason: Connectivity issues, carrier issues, T.38 incompatibility issue.

Troubleshooting steps:

• Retry.
• Determine whether the remote side was configured.

Invalid ECM response received from receiver

Meaning: The “Invalid ECM (Error Correction Mode) response received from receiver” error indicates that there’s an issue with the error correction process, where the receiving fax machine’s response to a request for error correction didn’t match expected parameters or was not understood by the sending machine.

Reason: Network or incompatibility issues.

Troubleshooting steps:

• Retry.
• If failures only occur with one number, there’s a chance that the remote fax machine is incompatible with our infrastructure.

Log entry lost

Meaning: The call started but the log entry for the call was lost or incomplete. In practice, this is rare and may indicate a system problem.

Reason: Internal Service Error.

Troubleshooting steps:

• Retry.
• If the issue persists, contact SignalWire support.

No response after sending a page

Meaning: The remote fax machine did not acknowledge that it received a page of the fax. Depending on the remote machine’s behavior, it may still have printed the page and any preceding pages.

Reason: Connectivity issues.

Troubleshooting steps:

• Retry.
• Contact destination to ensure delivery.

Received a DCN from remote after sending a page

Meaning: The remote fax machine responded with a disconnect message after a page was sent successfully. Depending on the remote machine’s behavior, it may have still printed the sent page and any preceding pages.

Reason: Poor network conditions.

Troubleshooting steps:

• Retry.
• If network conditions persist, contact SignalWire Support to reach out to our carrier peer.

Received no response to DCS or TCF

Meaning: The bulk fax service could not successfully determine the remote machine’s fax capabilities.

Reason: Network or incompatibility issues.

Troubleshooting steps:

• Retry.
• Determine whether the remote side was configured for supported fax protocols (T.38/T.30).
• Ensure the remote side’s network is stable.
• If failures only occur with one number, there’s a chance that the remote fax machine is incompatible with our infrastructure.

The call dropped prematurely

Meaning: The call dropped due to a non-fax transmission error. It is likely that the receiver hung up.

Reason: Inbound to SignalWire: the destination is a voice number or not set up to receive faxes. Outbound: the destination is a voice number, or the destination returns ringing for so long that the transmission times out before the handshake can be established.

Troubleshooting steps:

• Retry.

The HDLC carrier did not stop in a timely manner

Meaning: The fax service initiated a fax transmission with the receiver, but there was a synchronization (timing) error that could not be resolved.

Reason: Likely low-quality routes.

Troubleshooting steps:

• Retry.
• If network conditions persist, contact SignalWire Support to reach out to our carrier peer.

Timed out waiting for initial communication

Meaning: A call was established with the receiver, and the bulk fax service attempted to establish a fax session. However, there was no fax response from the receiver. This could be due to there being no fax machine on the receiving end or lack of call clarity.

Reason: No remote fax machine or poor quality routes.

Troubleshooting steps:

• Retry.
• If network conditions persist, contact SignalWire Support to reach out to our carrier peer.

Unexpected DCM after EOM or MPS sequence

Meaning: The remote fax machine disconnected unexpectedly after receiving a page of a multi-page fax. Depending on the remote machine’s behavior, it may have still printed the sent pages and any preceding pages.

Reason: Poor network conditions.

Troubleshooting steps:

• Retry.
• If network conditions persist, contact SignalWire Support to reach out to our carrier peer.

Unexpected DCN while waiting for DCS DIS

Meaning: “Unexpected DCN (Disconnect) while waiting for DCS (Digital Command Signal) or DIS (Digital Identification Signal)” implies that the fax machine received a disconnect signal unexpectedly during the initial negotiation phase, before the communication parameters were fully agreed upon.

Reason: Network or incompatibility issues.

Troubleshooting steps:

• Retry.
• Determine whether the remote side was configured for supported fax protocols (T.38/T.30).
• Ensure the remote side’s network is stable.
• If failures only occur with one number, there’s a chance that the remote fax machine is incompatible with our infrastructure.

Unexpected message received

Meaning: The fax service received a message that it did not expect given the current context.

Reason: Protocol failure.

Troubleshooting steps:

• Determine whether the expected number of pages matches the number of successfully transmitted pages. Failure may have been in tearing down the call.

Still having issues?

If you’ve worked through the troubleshooting steps above and the error persists, open a ticket with SignalWire Support and include the Fax SID from the last 24 hours so our team can investigate with our carrier peers.