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Home › Fax Troubleshooting

Fax Troubleshooting

Fax remains an important communication tool for some industries, which is why WebFones continues to support both electronic PDF faxing and physical fax machines. However, fax technology has limitations that are different from modern email or file sharing.

A fax transmission can fail for many reasons, including issues with the document being sent, the fax number being dialed, the receiving fax system, line quality, carrier compatibility, or restrictions on the remote fax machine. WebFones can help troubleshoot faxing problems, but some causes are outside of our control.

Before contacting support, please follow the troubleshooting steps below. These steps help determine whether the issue is with the WebFones fax service, the document being sent, or the receiving fax system.

Types of Faxing Supported

WebFones supports two types of faxing:

PDF Faxing

PDF faxing allows you to upload or send a PDF document electronically through the WebFones fax system.

PDF faxing works best when the document follows standard fax formatting:

  • Page size: 8.5 x 11 inches
  • Orientation: Portrait
  • Image resolution: 150 DPI or lower
  • File type: PDF
  • Avoid high-resolution scans, photos, graphics-heavy documents, oversized pages, or unusual page layouts

Even when a PDF meets these requirements, the receiving fax system may still have its own limitations that can cause the fax to fail.

Physical Fax Machine

A physical fax machine connects to the phone system and sends the fax as a traditional analog fax transmission.

Physical fax machines can experience different issues, including:

  • Poor scan quality
  • Paper feed problems
  • Incorrect fax machine settings
  • Remote fax negotiation failures
  • Long-distance or carrier-related issues
  • Problems with the receiving fax machine

Because PDF faxing and physical fax machines work differently, troubleshooting steps may vary depending on which method you are using.

Recommended PDF Fax Troubleshooting Steps

If a PDF fax fails, please complete the following steps before contacting support.

Step 1: Send a Simple Test Fax to WebFones

Create a simple one-page PDF that contains only the words:

TEXT FAX

The PDF should be:

  • 8.5 x 11 inches
  • Portrait orientation
  • Text-only
  • No images
  • No scans
  • No graphics
  • No high-resolution content

Send this test fax to the WebFones test fax number:

866-236-6345

This test helps confirm whether your WebFones fax service is able to send a basic fax successfully.

Step 2: If the Test Fax Succeeds, Send the Same Test PDF to the Destination Number

If the simple test fax succeeds when sent to the WebFones test number, send that same simple TEXT FAX PDF to the fax number you were originally trying to reach.

This helps determine whether the receiving fax number can accept a basic fax.

Step 3: Compare the Results

Use the results below to narrow down the cause of the problem.

If the simple test fax works to the WebFones test number and also works to the destination number:

Your fax service is working, and the destination fax system is able to receive a basic fax.

In this case, the problem is likely related to the original PDF document. Common causes include:

  • The PDF is not 8.5 x 11
  • The PDF is landscape instead of portrait
  • The PDF contains high-resolution images
  • The PDF was created from a large scan
  • The PDF contains photos or graphics
  • The file is too complex for reliable fax transmission
  • The receiving fax system has limits on page size, resolution, or document complexity

Try creating a lower-resolution version of the PDF, converting it to standard letter-size portrait format, or removing unnecessary images before sending again.

If the simple test fax works to the WebFones test number but fails to the destination number

This usually means the WebFones fax service is working, but the receiving fax system is not accepting the fax.

Possible causes include:

  • The remote fax machine is offline
  • The remote fax machine is out of paper or toner
  • The receiving fax line is busy
  • The destination number is incorrect
  • The receiving fax service is rejecting the transmission
  • The remote fax machine has compatibility or quality issues
  • The receiving fax system has restrictions that prevent the fax from completing

In this case, the issue is likely on the remote end and not with the WebFones fax service.

You may need to contact the recipient and ask them to confirm that their fax machine or fax service is working properly.

If the simple test fax fails to the WebFones test number

If a simple text-only fax fails to the WebFones test number, please contact WebFones support. This may indicate a problem with your fax configuration, account settings, fax number, device setup, or the WebFones fax service.

When contacting support, please include:

  • The fax number you are sending from
  • The fax number you are sending to
  • The date and time of the failed fax
  • Whether you are using PDF faxing or a physical fax machine
  • Whether the simple TEXT FAX test failed
  • A copy or description of the document you attempted to send
  • Any error message shown in the fax interface or on the fax machine

Document Formatting Guidelines for PDF Faxing

For best results, PDF fax documents should be prepared in a simple, standard format.

Recommended format:

  • Standard US letter size: 8.5 x 11 inches
  • Portrait orientation
  • Black-and-white or grayscale when possible
  • 150 DPI or lower
  • Text-based PDF when possible
  • Avoid photos, graphics-heavy pages, and large scanned images

Fax is not designed for high-resolution documents. A PDF that looks fine on a computer screen may still be too large, too detailed, or too complex for reliable fax transmission.

Why Fax Failures Happen

Unlike email, faxing requires a successful real-time connection between the sending fax system and the receiving fax system. Both sides must negotiate the transmission and complete the fax successfully.

A fax can fail because of issues on either side of the connection.

Common causes include:

  • Busy fax line
  • Remote fax machine turned off
  • Poor line quality
  • Carrier routing issues
  • Incorrect fax number
  • High-resolution or oversized document
  • Receiving system limitations
  • Compatibility problems between fax systems
  • Physical fax machine paper, toner, or scanning issues

Because the receiving fax system is not controlled by WebFones, a failed fax does not always mean there is a problem with the WebFones service.

When to Contact WebFones Support

Please contact WebFones support if:

  • A simple TEXT FAX PDF fails when sent to the WebFones test number
  • Multiple different destination fax numbers are failing
  • A physical fax machine cannot send any faxes
  • You believe your fax number or fax service is not configured correctly
  • You see repeated failures after completing the troubleshooting steps above

We want to know when something is legitimately not working. Completing the basic troubleshooting steps first helps us identify the cause more quickly and avoids spending time troubleshooting problems caused by a remote fax machine or an unsupported document format.

Summary

Before contacting support for a failed PDF fax:

  • Send a simple one-page PDF with the words TEXT FAX to 866-236-6345.
  • If that succeeds, send the same test PDF to the destination fax number.
  • If the test PDF works but your original PDF fails, reformat or simplify your document.
  • If the test PDF works to WebFones but fails to the destination number, the issue is likely with the receiving fax system.
  • If the test PDF fails to the WebFones test number, contact WebFones support.