Hi, i am from Germany and i use 3CX with some cisco phones 7940 series. Now we want to use some softphones from LANCOM named: LANCOM Advanced VOIP Client. All works great, but we have a problem when we transfer a call from a softphone to another extension, independent from target (CISCO or other softphone). When i try to transfer a call, then the person who will be transfered hears no on hold music, but the bell signal. And when the targetextension answers the phone, the person who should be transfered hears the on hold music and the transfer goes back to sourceextension. And we get this error in log: Code: [CM101000] Registration request from sip:firstname.lastname@example.org failed. Reason: Credentials don't match, check that authorization-ID and password match the ones in extension settings 22:40:53.724 AuthMgr::requestCredential [CM001005] Message SipReq: REFER 3cxPbx@192.168.0.1:5060 tid=02358569854d2a27 cseq=REFER email@example.com:5060 / 4 from(wire) failed authentication! Can you help me please? :roll: Nice greetings from near munich..