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Knowledge document #28

Cannot make outgoing calls

You can't make outgoing calls? The telephone does not work or the telephone number is not registered? ✔ Here's what to do.

You cannot make calls over the internet with a telephone or telephones connected to the FRITZ!Box, or it may not be possible to call only certain numbers. The problem either occurs sporadically or all the time. When it occurs, the telephone number may not be registered at that time and one of the following error messages or a different message referring to the telephone number may be displayed on the "Overview" page or in the event log of the FRITZ!Box:

  • "[number] telephone numbers active, none of these registered"
  • "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."

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

1 Installing the latest FRITZ!OS

  1. Install the latest FRITZ!OS on the FRITZ!Box.

2 Configuring a Telekom internet telephone number behind a Speedport Hybrid

The following step is only necessary if you are using the FRITZ!Box behind a Speedport Hybrid and your internet telephone numbers from Deutsche Telekom are no longer registered since updating FRITZ!OS:

  1. Follow the steps in the guide "Telekom internet telephone number behind a Speedport Hybrid are not registered".

3 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. If the tab is not displayed, the correct location information is automatically entered by your provider.
  4. Select your country from the drop-down list under "Location Information".
  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.

4 Restarting 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.

5 Enabling calls to international and premium numbers

IP telephones (for example FRITZ!App Fon) and telephones connected to a Mesh Repeater can only be used to make national calls and calls to emergency numbers. You can disable this security feature:

  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. Click on "Change selection" in the section "Security".
  5. Uncheck the boxes for all of the IP telephones that are allowed to dial international and premium numbers.
  6. Click "OK" to save the settings and on the FRITZ!Box, confirm that the procedure may be executed, if you are asked to do so.

6 Deleting call blocks

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Call Handling" in the "Telephony" menu.
  3. Delete call blocks for outgoing calls to individual numbers or ranges of numbers that you want to call.

7 Deleting carrier prefixes (provider prefixes)

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Call Handling" in the "Telephony" menu.
  3. Click on the "Provider Prefixes" ("Carrier Prefixes") tab.
  4. Delete all entries under "Global Provider Prefix" ("Global Carrier Prefix") and "Additional Provider Prefixes" ("Additional Carrier Prefixes").
  5. Click "Apply" to save the settings.

8 Entering the correct internet telephone number and login information

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephone Numbers" in the "Telephony" menu.
  3. Make a call and check whether numbers are configured or the status LED in front of the number is green or gray.
  4. If the LED is green, continue with the next section. The login information is entered correctly.

9 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 means that they do not make a requested function available for your line. This could be caused by the following reasons, for example:

  • The provider does not support the requested codec.
  • The provider does not support calls to the destination telephone number, for example calls to premium numbers.
  • The provider does not allow you to make more than one call at a time.

Therefore, the FRITZ!Box cannot solve this problem.

10 Connecting and configuring an analog telephone

The following steps are only necessary if the telephone is connected to an analog extension (for example "FON 1"):

Setting your analog telephone to tone dialing

  1. Set your device to "tone dialing" (DTMF) and not "pulse dialing". Pulse dialing is no longer state of the art and can lead to dialing problems on a telephone system. We therefore cannot guarantee the flawless operation of connected devices on the FRITZ!Box with pulse dialing. If tone dialing is selected, you hear a tone when you press a number key; with pulse dialing, you hear clicking sounds. Refer to the manufacturer of the device for information on how to set it up, for example consult the manual. 

Using only one connection option

"FON 1" and "FON 2" both have two options for connecting devices: You can either use the RJ11 socket on the back or the TAE socket on the side of the FRITZ!Box for the respective extension. You can only use one connection option at a time:

Example:
If you connected a telephone to the RJ11 socket for "FON 1", you cannot connect a device (for example a telephone, answering machine) to the TAE socket for "FON 1".

  1. If you connected devices to both of the sockets for the same extension, disconnect one of the devices from the FRITZ!Box.

11 Connecting and configuring an ISDN telephone

The following steps are only necessary if the telephone is connected to the "FON S0" socket:

Preparations

  1. Configure the telephone so you can send keypad sequences (sequences of characters and numbers, such as *121#) and enter special characters such as * and # with it. On many telephones, you can configure this function in the menu "Operation at a PBX > Dialing options > Dial * and #".

Disabling transmission of text information for ISDN telephones

During call setup, the FRITZ!Box transmits various text information to ISDN telephones. This allows you to see on the telephone display which number is currently being used to make a call, for example. However, some ISDN telephones do not process this text information correctly. Therefore, disable the function in the FRITZ!Box for testing purposes:

  1. Enter #960*0* on your telephone and press the call key (pick up the handset).
  2. Hang up again after about 3 seconds.

    Note:You can re-enable this function by entering #960*2*.

Disabling the energy-saving mode for ISDN telephones

The FRITZ!Box is equipped with a number of energy-saving mechanisms; for example, communication between the internal S0 bus and ISDN devices is terminated when there are no active connections. Some ISDN devices have problems with this function. Therefore, disable this function in the FRITZ!Box if ISDN devices are having problems establishing connections:

  1. Enter #966*1* on your telephone and press the call key (pick up the handset).
  2. Hang up again after about 3 seconds.

    Note:You can re-enable this function by entering #966*0*.

Resetting the ISDN telephone

  1. Delete all numbers (MSNs), call-by-call prefixes, and dialing rules on the telephone itself.

Connecting only an ISDN telephone

  1. Disconnect all devices (such as telephones, telephone systems, faxes) and cables from the "FON S0" socket.
  2. Connect a telephone to the "FON S0" socket. Do not use a telephone system or an ISDN distributor to connect the telephone to the FRITZ!Box.
  3. If you cannot make calls, continue with the next section. Do not connect the other ISDN devices yet.
    • If you can make calls, another device or its cable is defective, or a device is incorrectly configured, for example incorrect telephone numbers, dialing rules.
      1. Reconnect the other ISDN devices to find out which device causes the problem. Do not connect more than one ISDN device without its own power supply.
      2. If the error occurs again after you connect a particular ISDN telephone, that telephone or its cable is defective.
        • If the error occurs again after you connect a telephone system, the telephone system is either defective or incorrectly configured, for example incorrect telephone numbers, incorrect dialing rules, or call-by-call prefixes.

12 Defining telephone numbers for FRITZ!App Fon

  1. Start FRITZ!App Fon.
  2. Tap the the three-dot menu on the top right (Android) or "More" (iOS) and then tap "Settings".
  3. If you are using FRITZ!App Fon in iOS, tap "Telephone Numbers".
  4. If you are using FRITZ!App Fon in Android and use the app with several FRITZ!Boxes, first tap on the desired FRITZ!Box.
  5. Under "Outgoing calls", select the number to be used by FRITZ!App Fon for making calls.
  6. Under "Incoming Calls", specify which telephone numbers FRITZ!App Fon should react to when you receive calls.

13 Reconfiguring your telephone

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephony Devices" in the "Telephony" menu.
  3. Delete the telephone that you cannot make calls with. To do so, click the corresponding (Delete) button.
  4. Use the wizard to reconfigure the telephone: To do so, click the "Configure New Device" button and follow the instructions.

    Important:Do not use the wizard configure FRITZ!App Fon. FRITZ!App Fon is automatically set up again if you delete the app from your smartphone and reinstall it.

14 Disabling HD telephony

The following steps are only necessary if the problem occurs with a cordless telephone:

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephony Devices" in the "Telephony" menu.
  3. Click the (Edit) button for the respective telephone.
  4. Click on the "Telephony Device Features" tab.
  5. Click "Advanced Settings" to display all of the settings.
  6. Select the option "HD disabled" from the drop-down list in the section "HD Telephony".
  7. Click "Apply" to save the settings.

The FRITZ!Box is now fully configured for making calls over the internet. If you still have problems, your internet telephony provider may be experiencing technical difficulties.



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