Hello, I am having a issue where every so often calls will fail forwarding. This happens once in a while, when it stops working it gives this error
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.
After a while it will start working again, any ideas on this would be very helpful.
Thank you,
Based on the error message you’re seeing, here are the most common causes and troubleshooting steps for intermittent call transfer failures in Retell AI:
Telephony issues: Call transfer failures often occur for similar reasons as outbound call failures(1). The SIP connection log available in your call logs can help diagnose the specific failure reason(1).
Human detection timeout: If you have human detection enabled for warm transfers, the call may fail if a human isn’t successfully detected within the timeout period(1). This can happen if no human was actually present, the other party spoke after the detection timeout expired, or the speech was too similar to an IVR or voicemail(1).
Check your call logs: Review the detailed call logs for specific SIP error codes that can help identify the exact issue(2).
Verify transfer configuration:
transfer_call function to your agent’s function list(1)Test with different numbers: Try transferring to a different number to see if the issue is number-specific(2).
Review telephony provider logs: If using custom telephony, check with your provider’s logs and support team(2). The sources indicate there have been intermittent issues with specific telephony providers that required fixes from Retell’s engineering team(2).
Verify caller ID configuration: If you’re using caller ID override features, ensure your telephony provider supports this for your transfer type (warm vs cold)(3).
Since the issue is intermittent and resolves itself, this suggests it may be related to telephony provider connectivity or temporary network issues rather than a configuration problem on your end.