For a UCMA based application like SEFAUTIL Server to work correctly you will need to have the Skype for Business Server (Lync Server) DNS records in place: You will need to have one of the following records in place that resolves to your FE pool/server.

  • SRV    _sipinternaltls._tcp.{}
  • SRV    _sip._tls.{}
  • A         sipinternal.{}
  • A         sip.{}

If this is not setup you might get errors such as:
Microsoft.Rtc.Signaling.OperationFailureException:Automatic server discovery for the given sip user uri failed.