I evaluate hundreds of interactions a week. I am noticing a disturbing trend in our call recordings. Whenever our agents use the “Blind Transfer” button to send a customer to an external specialist (who is not on Genesys Cloud), the call drops completely about ten percent of the time. Our telecom team says it is an issue with the “SIP REFER” message, but they cannot explain why it only fails sometimes. Is there a known issue with how Genesys Cloud handles external SIP REFER transfers, and is there a setting we can change to force the transfer to complete more reliably?
I see these SIP issues pop up in my logs occasionally. The failure rate you are seeing is almost certainly related to how your specific carrier handles the REFER method. Some carriers require the Referred-By header to match a specific format, or they simply do not support the REFER message traversing their network boundaries if the destination is on a different provider. When the carrier rejects the REFER, Genesys Cloud drops the call because the agent has already disconnected from their leg of the transfer.
This is incredibly frustrating! we had this exact problem when transferring patients to external clinics. The most reliable fix is to completely disable the REFER method for external transfers. You can do this in your Trunk Configuration by unchecking the “Put Call on Hold for Transfer” or by changing the “Transfer Method” setting to force the Edge to bridge the call itself (often called “Tromboning”). It uses more bandwidth on your Edge, but it guarantees that the transfer succeeds even if the carrier’s SIP signaling is flaky.
Hi! I monitor the automated incident tickets generated from our trunks. I just want to add that if you switch to “Tromboning” the call, you must monitor your trunk capacity very closely! Tromboning ties up two SIP channels (one inbound, one outbound) for the entire duration of the external call, even after your agent has hung up. We accidentally exhausted our SIP trunk licenses the first day we made this change because we did not account for the doubled channel usage!