For the configuration of your fritzbox please follow the instructions below
- Click Telephony in the FRITZ!Box user interface.
- Click Telephone Numbers in the Telephony menu.
- Click the New Telephone Number button.
- Enable the option Internet telephone number and click Next.
- If there is a drop-down list to select an Internet telephony provider from, select your provider. If your provider is not included in the list, select Other provider.
Note: Whether the drop-down list is available and which providers are displayed depends on the regional options configured in the FRITZ!Box.
- Please enter the following Internet number (telephone number) and the account information (for example user name, password, registrar) in the corresponding fields.
Password: see above
- If present, you can enable the option Insert area code for outgoing calls. The area code is then automatically added when you make a call to a number that does not begin with “0”, so you do not have to dial it.
- Click Next and follow the Wizard’s instructions.
Please find more information here.