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Integrated fax transmission fails occasionally or always fails

Although you configured the the integrated fax function according to our guide, fax transmission fails occasionally or always fails. You either cannot send faxes at all, or only part of the faxes is sent. When a fax you are sending is aborted, one of the following error messages may be displayed, or one of the following error messages may be displayed in the event log of the FRITZ!Box:

  • "Transmission failed [0x3301]."
  • "Transmission failed [3495]."
  • "Transmission failed (0x3490)."
  • "An error occurred while sending a fax. Fax transmission was unsuccessful or incomplete."
  • "An error occurred. Error description: Fax transmission failed. Please enter your data again. If the error occurs again, please consult AVM Support."
  • "Not Acceptable Here (488)"
  • "Unsupported Media Type (415)"
  • "Not Acceptable Here (606)"

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

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

1 Entering your location information

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephone Numbers" in the "Telephony" menu.
  3. Click on the "Line Settings" tab.
  4. Select your country from the drop-down list under "Location Information". If your country is not listed, select "Other country".
  5. For the "Country code", enter the leading zeros in the first field and the country code in the second field (for example, enter "00" and "49" for Germany, see fig.).
  6. For the "Area code", enter the leading zero in the first field and the area code in the second field (for example enter "0" and "30" for Berlin, see fig.).

    Fig.: Entering the country code and area code (e.g. for Germany and Berlin)

  7. Click "Apply" to save the settings and on the FRITZ!Box, confirm that the procedure may be executed if asked to do so.

2 Using a different web browser

The problem may be caused by the web browser (for example plug-ins may be interfering):

  1. Test a different current web browser, for example Chrome or Firefox.

3 Testing different remote sites

  1. Test fax transmission to or from different fax machines on different telephone lines.
  2. If fax transmission only fails with a particular remote site, the fax machine at the remote site is either not ready to receive faxes or incorrectly configured.

4 Checking the event log of the FRITZ!Box

  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 for the fax that failed. If so, note the information that correspond to the message.
  5. If the message "Unsupported Media Type (415) is displayed, your provider does not support the requested codec or does not allow you to send faxes.
    • 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.

      Note:In this case, you can either use a telephone number from a provider that supports T.38 or disable T.38 again for fax reception. T.38 may not be necessary for fax transmission.

5 Checking the protocol for fax transmission

The following steps are only necessary if you are trying to send and receive faxes with an internet telephone number:

  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.