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Integrated fax reception fails occasionally or always fails

Although the integrated fax function was set up according to our guide, fax reception fails occasionally or always fails. Either you cannot receive faxes at all, or received faxes are cut off. One of the following error messages may be displayed in the event log of the FRITZ!Box:

  • "Not Acceptable Here (488)"
  • "Not Acceptable Here (606)"
  • "Unsupported Media Type (415)"
  • "Email delivery failed. [Message]"
  • "Error while saving the message on USB storage."
  • "An error occurred during fax reception. The document was not received or is incomplete."

Simply proceed as described below. After each measure, check whether the problem is solved.

1 Checking the event log of the FRITZ!Box

Restarting the FRITZ!Box

Since some error messages are only displayed once in the event log, restart the FRITZ!Box:

  1. Click "System" in the FRITZ!Box user interface.
  2. Click "Backup" in the "System" menu.
  3. Click on the "Restart" tab.
  4. Click the "Restart" button.

Checking the event log for error messages

As soon as fax reception fails for the first time after the restart, check whether the failed attempt was answered with an error message. Then, follow the instructions given for the error message you received:

  1. Click "System" in the FRITZ!Box user interface.
  2. Click "Event Log" in the "System" menu.
  3. Select "Telephony" from the drop-down list.
  4. Check whether one of the following error messages is displayed.
  5. If the message "An error occurred during fax reception. The document was not received or is incomplete" is displayed although you received the entire fax, there is no error. Some data packets were lost during fax transmission. In this case you can ignore the message.
    • If the message "Email delivery failed. [message]" is displayed, correct your email account information for the push service. The fax was not forwarded by email because the email address or the login information for your email account was not correctly entered for the push service.
    • If the message "Error while saving the message to the USB storage medium" is displayed, connect a different USB storage device, preferably a USB memory stick, to the FRITZ!Box for testing purposes. The fax was not copied to the USB storage device because data cannot be written to it.
    • If the message "Unsupported Media Type (415) is displayed, your provider does not support the requested codec or generally does not allow fax transmission.
    • If the message "Not Acceptable Here (488 or 606)" is displayed, your provider does not support the T.38 standard. Without T.38, reliable fax transmission over the internet is not possible.

2 Checking the protocol for fax transmission

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephone Numbers" in the "Telephony" menu.
  3. Click on the "Voice Transmission" tab.
  4. Look for the aborted faxes under "Details on Completed Calls" and check whether "T.38" is displayed in the "Coding" column for these faxes:
  5. If "T.38" is displayed, T.38 was used for the fax transmission.
    • If "T.38" is not displayed, T.38 was not used. Without T.38, reliable fax transmission over the internet is not possible.

      Note:If your internet telephony provider does not support T.38, for the fax you can use an internet number of an internet telephony provider that supports T.38.