I am getting this message when trying to transfer ...
# ❓・ai-evy-supports
Sanjay
01/30/2026, 4:07 PM@AI Evy I am getting this message when trying to transfer a call - "status":"Transfer call cannot be completed, probably don't have the permission to perform the transfer.. Please inform the customer that the transfer did not go through and offer to try again or assist them directly."}
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AI Evy
01/30/2026, 4:07 PMThanks for tagging me @Sanjay. I'll look through relevant sources and get back to you shortly.
AI Evy
01/30/2026, 4:08 PM### Answer
This error typically indicates a telephony provider configuration issue rather than a Retell AI problem. [(1) ]() , [(2) ]()
Common causes:
1. SIP trunk configuration issues - If you're using a SIP-trunked number, your trunking settings may need adjustment (e.g., outbound transport method, termination URI uniqueness) . [(1) ]()
2. Telephony provider restrictions - The error often originates from your provider (Twilio, Telnyx, etc.) not allowing the transfer. For example, Telnyx may return errors like "Unverified origination number" which you'd need to resolve with them directly.
3. Warm transfer requires additional permissions - If you're using warm transfer, this requires more permissions from your telephony provider compared to cold transfer. Cold transfer may work while warm transfer fails due to these additional requirements. [(2) ]()
Troubleshooting steps:
- **For SIP trunk users**: Try changing the outbound transport method to either TCP or UDP, and ensure your termination URI is unique. [(1) ]()
- **For Twilio users**: Verify the number you're transferring to is added to your verified numbers in your Twilio account. [(2) ]()
- **For warm transfer specifically**: If cold transfer works but warm transfer doesn't, contact your telephony provider about enabling the necessary permissions for warm transfer.
- **Consider using Retell-purchased numbers**: The "Transferee's Number" caller ID display feature for warm transf
AI Evy
01/30/2026, 4:08 PMers is fully supported for Retell-Twilio numbers. For custom telephony, you may need to contact your provider.
Could you share:
- What telephony provider you're using?
- Whether this is a SIP-trunked number?
- Whether you're attempting a cold or warm transfer?
AI Evy
01/30/2026, 4:08 PM
To learn more, see the sources I considered:
[[1] Transfer Call Permission Error - Need Configuration Assistance](https://discord.com/channels/1186424376300679209/1450235811470770359)
[[2] Warm transfer](https://discord.com/channels/1186424376300679209/1436106645632450671)
AI Evy
01/30/2026, 4:08 PMFeel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.