Inbound BYOC Cloud calls are tagged with the site-id header of the site that is connected to the trunk that has the outbound route. So, because the site’s number plan is applied to inbound calls, any call that matches that number plan entry gets associated with the wrong site. When this happens, the DNIS can be normalized with the wrong number plan entry, which in turn can cause the number not to match one of the assigned DIDs. If the DID isn’t matched, the Edge sends a SIP 404 message back to the carrier causing the caller to hear an out-of-service message.

To avoid this situation in BYOC Cloud, you need to make sure that the outbound route is only associated with a single site.