Our E-mail to Fax service allows you to take a file on your computer, such as a PDF, and convert it to a fax that can be sent to any phone number that is configured to receive faxes, such as a number pointed to a traditional fax machine. All you need to do is register an e-mail address in your BackOffice, open up any e-mail client, type in your destination, attach your file and click send. It’s really that simple. Let’s get started with our walkthrough for this service.





The subject and body fields are not used, and will be ignored. Also, I attached a PDF file from my PC to the message. For best results, please ensure that your attached file’s dimensions are 8.5 x 11 inches, and its filename is no greater than 32 characters. Also, be sure that there’s only one attachment per e-mail, as additional attachments will not be sent. Your file attachment can include multiple pages. We recommend less than 30 total pages, as a higher page count may result in a greater chance of failure.

If any of these prerequisites are not met, you may receive error messages after sending your e-mail.

After sending the message, you will receive an e-mail letting you know that your message has been queued. Afterwards, you will receive another e-mail that includes the results of your fax attempt, whether it succeeded or failed.

What your Gmail should look like when sending and Email to Fax


E-mail to Fax Troubleshooting

Should you receive a failure, you will receive a bounce-back e-mail that includes a reason for the failure. Here are some of the reasons as to why this may have occurred.

  • Incorrectly configured/missing SPF record.
    • VoIP Innovations checks for a valid SPF record on every E-mail to Fax attempt in order to prevent spam/fraud. If you are sending from a domain that does not have a valid SPF record, your bounce-back message will include something like this:
      • Remote Server returned '< #5.3.0 x-unix; SPF records for sender are improperly configured>'
    • For additional information on SPF records, please see our SPF Record for Email to Fax Wiki article.
  • Sender is not authorized in VI’s BackOffice.
    • If you are trying to send an E-mail to Fax attempt from an e-mail address that is not registered in our BackOffice, you will receive an error that looks like this:
      • Remote Server returned '< #5.3.0 x-unix Source address not authorized>
    • To remedy this, follow the steps to register an e-mail address that are outlined in the beginning of this article.
  • The call was unable to negotiate T38. Error Received : T38_NEG_ERROR
    • This usually occurs when the call did not properly negotiate the T38 protocol, which is necessary for faxing using our E-mail to Fax service. You may want to try dialing the destination number from a handset phone to check if you are receiving fax tones. If you are, and the E-mail to Fax still fails, try opening a ticket with Support and provide the call to, call from, and time of call.
  • The outbound call failed.
    • If your E-mail to Fax attempt fails with “Outgoing call failed”, check to verify that the destination is a valid/working number. After verifying this and checking for fax tones, open a ticket with Support if any issues persist.
  • Attachment file is the wrong format
    • You may see this error if the file you are trying to attach is not the correct format. The supported file types are:
      • PDF, DOC, DOCX, XLS, XLSX, RTF, PPT, PPTX, and TIFF (Fax-formatted)
      • If you are still having issues with your file, you may want to convert it using a program such as CutePDF.
    • Instructions on how to use this program are detailed in our Email to Fax Wiki article.