SIP
199 Early Dialog Terminated
A UAS can send this to indicate that an early dialog has been terminated. Used when forking results in multiple early dialogs.
Когда вы видите этот код
In forked call scenarios when one of the forked branches is cancelled because another branch was answered.
Как исправить
No action needed. This is normal behavior in forked call setups. Ensure your UA handles early dialog termination gracefully.