### Answer To test transfer failure behavior in a conversation flow, you can use the pre-populated edge that exists for transfer failures. The Call Transfer Node has a transition that happens when transfer fails—there's already a pre-populated edge for this that you can connect to a node to handle transfer failure. [(1) ]() For testing, you could: 1. Transfer to an invalid or unreachable number – This will trigger the failure path since the transfer won't complete successfully. 2. Use a number that won't pick up – If human detection is enabled, the call may fail if a human is not successfully detected. Possible reasons include no human actually being present (e.g., it was an IVR or voicemail) , the other party speaking only after the detection timeout expired, or speech being too similar to an IVR/voicemail. [(2) ]() 3. Set a short ring timeout – If your global call settings have a ring duration configured, transferring to a number that takes longer to answer than the timeout will trigger a failure. [(3) ]() Note that call transfer only works during phone calls, not web calls. [(1) ]() [(2) ]()

​ To learn more, see the sources I considered: [[1] Call Transfer Node](https://docs.retellai.com/build/conversation-flow/call-transfer-node) [[2] Debug call transfer failure](https://docs.retellai.com/reliability/call-performance) [[3] Failed Transfers](https://discord.com/channels/1186424376300679209/1448474483156324373) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.