Hi, hitting a wall on BYOC inbound for a Paraguay DID. Would love guidance from anyone who set this up with a non-Twilio SIP carrier. Setup: Paraguay (+595) DID from an external SIP carrier (not Twilio). Imported via POST /import-phone-number with termination_uri, SIP auth, and inbound_agent_id — per BYOC docs. Standard retell-llm agent, Spanish, custom tools. What works: Web test calls → agent answers, LLM + tools + voice all fine. Outbound calls through the SIP trunk connect correctly to PSTN. Proves trunk credentials and import-phone-number config are right. What doesn't work: Inbound calls to the DID fail immediately — no ringback, call drops. No inbound call entry in the Retell dashboard. Questions: Is Paraguay (+595) / LATAM supported for BYOC inbound? Any regional restriction? For BYOC inbound with a non-Twilio carrier, what does Retell expect on the inbound leg? Does Retell REGISTER against the carrier so incoming INVITEs route back? Or does the carrier forward INVITEs to a specific Retell SIP URI / IP? If so, which one? Any IP allowlist required on the carrier side for Retell's SIP signaling / media? Any extra Retell-side config beyond import-phone-number + inbound_agent_id? Has anyone gotten BYOC inbound working with a non-Twilio carrier (Zadarma, VoIP.ms, Telnyx resold, LATAM provider)? A pointer to the exact inbound destination Retell expects would be huge. Thanks!