DTMF / Tone Dialing

Outgoing Calls: DTMF / Tone Dialing Not Working

Problem: The tone dialing system of the called service uses a different DTMF setting than what is configured in the FritzBox, or the automatic detection of the tone dialing method is not working.

Solution: FritzBox → Web interface → Settings → Telephony → Internet Telephony / Own Phone Numbers → select the corresponding number/account
DTMF: change "auto" to "RTP" or "inband"