FRITZ!App Fon Service - Knowledge Base

FRITZ!App Fon Service

Cannot make outgoing calls

You cannot use FRITZ!App Fon to make calls over the Internet. One of the following error messages or another message regarding the telephone number may be displayed in the event log of the FRITZ!Box:

  • "Registration of Internet telephone number [number] failed. Reason for error: DNS error"
  • "Registration of Internet telephone number [number] failed. Reason for error: Remote site not responding. Timeout."
  • "Registration of Internet telephone number [number] failed. Remote site reports reason for error: [40x, 50x, 500, 503]"
  • "Internet telephony registration failed [number] Reason for error: [401, 402, 403]"
  • "Internet telephony with [Number] failed. Reason for error: [404, 405, 406, 407, 408, 50x]"
  • "Internet telephony with [number] via [registrar] failed. Reason for error: Not Acceptable Here (488)"
  • "Internet telephony with [number] via [registrar] failed. Reason for error: Timeout: The call was not accepted. [Message]"
  • "Internet (telephony) connection cleared."

Important:Some of the settings described here are only displayed if the advanced view is enabled in the user interface.

Simply proceed as described below. After each measure, check whether the issue persists.

1 The provider rejects the call attempt

This section only applies if the message "Internet telephony [...] failed. Reason for error: Not Acceptable Here (488)" is displayed under "System > Event Log" in the FRITZ!Box user interface when the error occurs. This message from your provider indicates that it does not make a requested function available for your line. This may be due to the following reasons, for example:

  • The provider does not support the requested codec.
  • The provider does not permit calls to the destination number, for example calls to premium numbers.
  • The provider does not allow you to make simultaneous calls.

Therefore, the FRITZ!Box cannot resolve this issue.

2 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 included in the list, select "Other country".
  5. For the "Country code", enter the country code prefix in the first field and the country code in the second field (for example for Germany "00" and "49", see fig.).
  6. For the "Area code", enter the area code prefix in the first field and the area code in the second field (for example for Berlin "0" and "30", see fig.).

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

  7. Click "Apply" to save your settings.

3 Restarting the FRITZ!Box

  1. Click "System" in the FRITZ!Box user interface.
  2. Click "Backup" or "Reset" in the "System" menu.
  3. Click on the "Restart" tab (if available).
  4. Click the "Restart" button.

4 Setting up FRITZ!App Fon

Defining telephone numbers for FRITZ!App Fon

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephony Devices" in the "Telephony" menu.
  3. Click the button (Edit) for FRITZ!App Fon. When it was installed, FRITZ!App Fon was automatically configured with the telephone's device name on the "LAN/WLAN" port in the FRITZ!Box.
  4. From the drop-down list "Outgoing Calls", select the number to be used by FRITZ!App Fon for making calls.
  5. Select the numbers that FRITZ!App Fon should react to when you receive calls.
  6. Click "OK" to save the settings.

Disabling HD telephony

The following steps are only necessary if the issue occurs when using FRITZ!App Fon with an iOS device:

  1. Start FRITZ!App Fon.
  2. Tap "More" and then "Settings".
  3. Disable the option "HD telephony".

Enabling alternative microphone

The following steps are only necessary if the issue occurs when using FRITZ!App Fon with an Android device:

  1. Start FRITZ!App Fon.
  2. Tap "More" and then "Settings".
  3. Tap the menu key on the telephone and then tap "Advanced".
  4. Enable the option "Alternative microphone".

5 Reconfiguring your telephone

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephony Devices" in the "Telephony" menu.
  3. Delete FRITZ!App Fon from the list of telephony devices. To do so, click the corresponding (Delete) button.
  4. Stop FRITZ!App Fon from running in the background.
  5. Start FRITZ!App Fon. FRITZ!App Fon is automatically reconfigured when you start it.

The FRITZ!Box is now completely configured for making calls over the Internet. If the issue persists, your Internet telephony provider may be experiencing technical difficulties.