Troubleshooting- HTTPS Fax

Updated at August 26th, 2026

Prerequisites 

  • If a client is using a physical fax machine with an Analog Telephone Adapter (ATA),  a new number or an existing number will need to be ported to the HTTPS Fax service and will require a user for the number and ATA.
 

 

If a fax you sent through your HTTPS Fax account does not go through, you will receive an error notification by email or in your fax activity log. This guide explains what each error means and what steps to take.

Steps

  1. Locate the error message in your fax activity or notification
  2. Identify the error type
  3. Follow the recommended action based on the error category

Before You Resend

Run through this quick checklist before looking up your error message:

  • Confirm the fax number is correct including the area code
  • Confirm the destination fax machine is on, has paper loaded, and is set to receive
  • Try calling the destination number from a regular phone to confirm it is active and returns a fax tone
  • Confirm your file is in a supported format (PDF, TIF, and standard document formats are accepted)

 What to Provide to Support

  • The destination fax number
  • The exact error message from the fax activity or notification email
  • The date and time of the failed attempt
  • Whether the issue affects all destinations or only a specific number
  • Whether inbound faxes are working normally.

Error Message Explanation

Errors typically fall into three categories:

  • Number / destination issues
  • Temporary network issues
  • System or compatibility issues

Error message

Explanation

Action

File conversion error

This cause indicates that the file cannot be converted to a fax.

Check attachment

Unallocated number

This cause indicates that the called party cannot be reached because it is not currently assigned.

Check destination number and resend

No user responding

This cause is used when a called party does not respond to a call establishment message within the prescribed amount of time.

Check destination number and resend

Number changed

This cause is returned when the called party number is no longer assigned.

Check destination number and resend

Invalid number format

This cause indicates that the called party cannot be reached because the number is not in a valid format or is not complete.

Check destination number and resend

Facilities rejected

This cause is returned when a supplementary service requested by the user cannot be provided by the network.

Check destination number and resend

Call rejected

This cause indicates that the equipment sending this cause does not wish to accept this call, although it could have accepted the call.

Check destination number and resend

Transmission error

This cause indicates communication errors, like line noise or packet loss, etc., during fax transmission.

Resend or Try Again Later

User busy

This cause is used to indicate that the called party is unable to accept another call because the user busy condition has been encountered.

Resend or Try Again Later

No circuit/channel available

This cause indicates that there is no appropriate circuit/channel presently available to handle the call.

Resend or Try Again Later

Destination out of order

This cause indicates that the destination indicated by the user cannot be reached because a signal message was unable to be delivered to the remote party. This may be due to equipment failures at the remote party or user equipment off-line.

Contact Receiver & confirm they are able to receive faxes. Then resend

Outgoing calls barred

This cause indicates that outgoing calls are not allowed.

Contact Support

Originator cancel

This cause is used to indicate that the call was canceled by the sender.

Contact Support

Incompatible destination

This cause indicates that the receiving equipment has a compatibility issue (e.g. data rate) and so a call cannot be established.

Contact Support

Exchange routing error

This cause indicates that the destination cannot be reached because an intermediate exchange has released the call.

Contact Support or Try Again Later

Recovery on timer expiry

This cause indicates that a procedure has been initiated by the expiration of a timer in association with error handling procedures.

Retry and if fails again please Contact Support

 

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