From f947f5ab0aafe2652b27f4a9b3983ba0597cc04f Mon Sep 17 00:00:00 2001 From: manny-r31 Date: Fri, 12 Jun 2026 14:05:54 -0400 Subject: [PATCH] Reordered, added warning and link to create support ticket if necessary --- .../pages/calling/fax/common-fax-errors.mdx | 217 +++++++++--------- 1 file changed, 114 insertions(+), 103 deletions(-) diff --git a/fern/products/platform/pages/calling/fax/common-fax-errors.mdx b/fern/products/platform/pages/calling/fax/common-fax-errors.mdx index 03bbece50c..0809cde453 100644 --- a/fern/products/platform/pages/calling/fax/common-fax-errors.mdx +++ b/fern/products/platform/pages/calling/fax/common-fax-errors.mdx @@ -3,29 +3,42 @@ id: ca36587f-5d99-47de-9f43-ba779e5146eb slug: /fax/common-errors title: Common fax errors description: Our guide to understanding and troubleshooting the most common fax error messages. +max-toc-depth: 3 x-custom: ported_from_readme: true tags: - product:fax --- -The table below lists some of the most common fax error messages along with the likely reason and some troubleshooting steps for resolution. +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. + +**Per our carrier peers' requirements, these SIDs MUST be from the last 24 hours**. SIDs older than 24 hours cannot be investigated. + -If these steps to resolve your issue do not help, SignalWire Support can investigate what went wrong with our carrier peers. -Please open a support request and include the Fax SID with the error. _Per our carrier peers' requirements, these SIDs MUST be from the last 24 hours._ - -## List of common errors +## Common errors ### Connection Failed -**Meaning:** There was not receiver on the other end of the call to connect to. +**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:** +**Troubleshooting steps:** + +- Retry. +- Contact the owner of the destination number to confirm compatibility and connectivity. + +### Disconnected after permitted retries -- Retry -- Contact the owner of the destination number to confirm compatibility and connectivity +**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 @@ -33,149 +46,144 @@ Please open a support request and include the Fax SID with the error. _Per our c **Reason:** Internal Service Error. -**Troubleshooting Steps:** +**Troubleshooting steps:** -- Retry -- If the issue persists, contact SignalWire support +- Retry. +- If the issue persists, contact SignalWire support. -### Failed to train with any of the compatible modems +### Document loading error -**Meaning:** A remote fax machine was detected, but the sending and receiving modems could not establish communication. +**Meaning:** The fax service attempted to generate the message to send but a document was missing. -**Reason:** Connectivity issues. +**Reason:** Internal Service Error. -**Troubleshooting Steps:** +**Troubleshooting steps:** -- Retry -- If the issue persists, contact SignalWire support +- Retry. +- If the issue persists, contact SignalWire support. -### Fax transmission not established +### Failed to train with any of the compatible modems -**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. +**Meaning:** A remote fax machine was detected, but the sending and receiving modems could not establish communication. -**Reason:** Connectivity issues, Carrier issues, T.38 Incompatibility issue. +**Reason:** Connectivity issues. -**Troubleshooting Steps:** +**Troubleshooting steps:** -- Retry -- Determine whether remote side was configured +- Retry. +- If the issue persists, contact SignalWire support. -### Log entry lost +### Far end cannot receive at the resolution of the image -**Meaning:** The call started but the log entry for the call was lost/incomplete. In practice, this is rare and may indicate a system problem. +**Meaning:** The remote fax machine does not support receiving faxes sent by our service. -**Reason:** Internal Service Error +**Reason:** Quality is too high. -**Troubleshooting Steps:** +**Troubleshooting steps:** -- Retry -- If the issue persists, contact SignalWire support +- Try lowering quality (resolution is known as "quality" in Programmable Fax). -### No response after sending a page +### Fax transmission not established -**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. +**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 +**Reason:** Connectivity issues, carrier issues, T.38 incompatibility issue. -**Troubleshooting Steps:** +**Troubleshooting steps:** -- Retry -- Contact destination to ensure delivery +- Retry. +- Determine whether the remote side was configured. -### Received no response to DCS or TCF +### Invalid ECM response received from receiver -**Meaning:** The bulk fax service could not successfully determine the remote machine's fax capabilities +**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 -- Determine whether the remote side was configured for supported fax protocols (T.38/T.30). -- Ensure the remote side's network is stable. +**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 -### The call dropped prematurely +**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. -**Meaning:** The call dropped due to non-fax transmission error. It is likely that the receiver hung up. +**Reason:** Internal Service Error. -**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:** -**Troubleshooting Steps:** Retry. _Note: SignalWire Fax only supports the transmission of PDFs to fax-enabled destinations._ +- Retry. +- If the issue persists, contact SignalWire support. -### The HDLC carrier did not stop in a timely manner +### No response after sending a page -**Meaning:** The fax service initiated a fax transmission with the receiver, but there was synchronization (timing) error that could not be resolved. +**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:** Likely low-quality routes. +**Reason:** Connectivity issues. -**Troubleshooting Steps:** +**Troubleshooting steps:** -- Retry -- If network conditions persist, contact SignalWire Support to reach out carrier peer +- Retry. +- Contact destination to ensure delivery. -### Timed out waiting for initial communication +### Received a DCN from remote after sending a page -**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. +**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:** No remote fax machine or poor quality routes. +**Reason:** Poor network conditions. -**Troubleshooting Steps:** +**Troubleshooting steps:** -- Retry -- If network conditions persist, contact SignalWire Support to reach out to carrier peer +- Retry. +- If network conditions persist, contact SignalWire Support to reach out to our carrier peer. -### Unexpected DCN while waiting for DCS DIS +### Received no response to DCS or TCF -**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. +**Meaning:** The bulk fax service could not successfully determine the remote machine's fax capabilities. **Reason:** Network or incompatibility issues. -**Troubleshooting Steps:** -- Retry +**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. -### 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. +### The call dropped prematurely -**Troubleshooting Steps:** +**Meaning:** The call dropped due to a non-fax transmission error. It is likely that the receiver hung up. -- Retry -- If network conditions persist, contact SignalWire Support to reach out to carrier peer +**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. -### Far end cannot receive at the resolution of the image +**Troubleshooting steps:** -**Meaning:** The remote fax machine does not support receiving faxes sent by our service. +- Retry. -**Reason:** Quality is too high. +**Note:** SignalWire Fax only supports the transmission of PDFs to fax-enabled destinations. -**Troubleshooting Steps:** Try lowering quality (Resolution is known as "quality" in Programmable Fax). +### The HDLC carrier did not stop in a timely manner -### Received a DCN from remote after sending a page +**Meaning:** The fax service initiated a fax transmission with the receiver, but there was a synchronization (timing) error that could not be resolved. -**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:** Likely low-quality routes. -**Reason:** Poor network conditions. +**Troubleshooting steps:** -**Troubleshooting Steps:** +- Retry. +- If network conditions persist, contact SignalWire Support to reach out to our carrier peer. -- Retry -- If network conditions persist, contact SignalWire Support to reach out to carrier peer +### Timed out waiting for initial communication -### Unexpected message received +**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. -**Meaning:** The fax service received a message that it did not expect given the current context. +**Reason:** No remote fax machine or poor quality routes. -**Reason:** Protocol failure. +**Troubleshooting steps:** -**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. +- Retry. +- If network conditions persist, contact SignalWire Support to reach out to our carrier peer. ### Unexpected DCM after EOM or MPS sequence @@ -183,31 +191,34 @@ parameters were fully agreed upon. **Reason:** Poor network conditions. -**Troubleshooting Steps:** +**Troubleshooting steps:** -- Retry -- If network conditions persist, contact SignalWire Support to reach out to carrier peer +- Retry. +- If network conditions persist, contact SignalWire Support to reach out to our carrier peer. -### Document loading error +### Unexpected DCN while waiting for DCS DIS -**Meaning:** The fax service attempted to generate the message to send but a document was missing. +**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:** Internal Service Error +**Reason:** Network or incompatibility issues. -**Troubleshooting Steps:** +**Troubleshooting steps:** -- Retry -- If the issue persists, contact SignalWire support +- 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. -### Invalid ECM response received from receiver +### Unexpected message received + +**Meaning:** The fax service received a message that it did not expect given the current context. -**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:** Protocol failure. -**Reason:** Network or incompatibility issues. +**Troubleshooting steps:** -**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. -- Retry -- If failures only occur with one number, there's a chance that the remote fax machine is incompatible with our infrastructure. +## Still having issues? + +If you've worked through the troubleshooting steps above and the error persists, [open a ticket with SignalWire Support](https://support.signalwire.com) and include the Fax SID from the last 24 hours so our team can investigate with our carrier peers.