SIP
608 Rejected
An intermediary machine or process rejected the call attempt. Similar to 607 but the rejection comes from the network rather than the end user.
Когда вы видите этот код
When a network element (not the callee) blocks the call. Used by analytics engines and call-blocking services in the network path.
Как исправить
This is a network-level block. Contact the network administrator or carrier to understand why the call was blocked.