Currently, my office is running Mediant1000 and 3cx Version 5.1 smoothly. I was trying out the version6 but faces a weird problem. Version6 works fine usually for the first 3-4 hours. After that, error starts, Call(111): Incoming call rejected, caller is unknown; msg=SipReq: INVITE firstname.lastname@example.org tid=ac1373442940 cseq=INVITE email@example.com / 2 from(wire)<br> CallCtrl:nIncomingCall:[CM502001]: Source info: From: 111; To: <sip:firstname.lastname@example.org>;tag=1c1366462679<sip:email@example.com><br> This caused the line to cut off (incoming and outgoing). and the only way to resolved this is by a reboot. There is no error on the operating system side. Anyone have any idea why?