SIP
600 Busy Everywhere
The callee's end system was contacted successfully but the callee is busy and does not wish to take the call at this time. Unlike 486 (Busy Here), this is a definitive response.
Bu Kodu Gördüğünüzde
When the callee has rejected the call on all devices. No other endpoints should be tried. The user is universally busy.
Nasıl düzeltilir
Wait and try again later. No alternative contact points exist. The callee must become available on their own.