I cannot dial phone calls over the Internet. The FRITZ!Box event log shows the message "Remote site reports reason for error 500." What can I do?

If you are unable to dial a call over the Internet from a telephone connected to FRITZ!Box, and under "System/Events" in the FRITZ!Box user interface you find the error message "Registration of Internet number failed. Reason for error: 500," then please carry out the steps described here.

Correct the entry for the Internet telephony provider's registrar

1. Open the FRITZ!Box user interface.
2. Click on "Settings".
3. ("Advanced Settings" >) "Telephony" > "Internet Telephony"
4. Click on the "Edit" icon next to the Internet number you want to use to dial outgoing calls.
5. In the "Registrar" field, enter the name of the Internet telephony registrar exactly as it appears in the information you received from your Internet telephony provider.
6. Click "Apply".
   NOTE:
   If you select any of the pre-configured entries in the list of Internet telephony providers, FRITZ!Box automatically enters the registrar, which is not displayed in the configuration. In this case, make sure that the Internet telephony provider you selected is the one you actually use.

Make sure that FRITZ!Box can connect to the Internet

1. Check whether the "Power" LED on your FRITZ!Box is lit steadily. If the "Power" LED is blinking, continue with the instructions here.
2. Open the FRITZ!Box user interface.
3. Click on "Settings".
4. ("Advanced Settings" >) "Internet" > "Account information"
5. Activate the options "Use one Internet connection for all computers (router)" and "Account information required (PPPoE/PPPoA connection)".
6. Enter the correct access information for your Internet service provider.

Contact your Internet telephony provider