There can be many reasons for faults during outgoing telephone calls.

  •     First of all, please test whether the incoming calling is working.
  •     If not, please follow the steps described in this manual.
  •     If the malfunction occurs when dialing special or service numbers, please click here.
  •     Test whether an alternative VoIP-enabled device, e.g. a softphone or a VoIP app, is working.

If the problem persists afterwards, please send us a current call example with the key data from this help article to