Retell Telephony And Call Lifecycle

Integrator uses custom telephony and tries to dial the SIP URI for an inbound call without first calling Register Phone Call.

Call Register Phone Call first to bind the agent and obtain the call_id used to construct the SIP URI; only then dial. The registration tells Retell which agent handles the call. Skipping it leaves Retell without the agent binding.

After Register Phone Call, the dialer is delayed in a queue and connects the SIP call ~8 minutes later.

Dial within the registration validity window (docs state ~5 minutes); a late connection disconnects with registered_call_timeout. Re-register if the dial will be delayed. [REQUIRES-VERIFICATION on the exact current window duration.]

A phone number is bound to one agent, but the operator wants different agents for inbound vs outbound on that number.

Configure inbound and outbound agents separately (Retell supports distinct inbound/outbound agents, with the option to disable either). Do not assume one agent field covers both directions; verify each direction routes to its intended agent.