I inherited this Genesys Cloud org six months ago and I am currently being haunted by ‘Ghost Calls’. We are seeing cases where an agent’s WebRTC phone rings and they click ‘Answer’, but the audio is silent and the interaction disappears from their screen after two seconds. I’ve looked at the SIP logs and I see a ‘481 Call/Transaction Does Not Exist’ error coming from our Edge. This happens about ten times a day across different agents. Our network team says there are no packet drops. Why is the Edge telling the platform that a call ‘Does Not Exist’ when it just signaled the agent to answer it?
Hey! Stackoverflow style help here. I manage our email templates but I’ve tinkered with the SIP logs enough to know that a ‘481’ usually means a ‘Late ACK’ or a ‘Timed-out Invite’. If the agent’s browser takes too long to respond to the SIP ‘Invite’ (maybe because of high CPU or a slow Chrome extension), the Edge will timeout and send a ‘Cancel’. If the agent then clicks ‘Answer’ a millisecond later, the session is already dead on the Edge side, hence the ‘Does Not Exist’ error. You should check the ‘SIP ACK Timeout’ in your Edge configuration—increasing it from 500ms to 2000ms usually banishes these ghosts!
I’m an outbound API developer and I’ve seen this happen with our automated contact lists when the ‘Dialer’ gets too aggressive. If you have ‘Auto-Answer’ enabled for your agents, but their browser is being throttled by the OS (common on laptops with power-saving mode), the ‘Auto-Answer’ signal arrives at the Edge after the SIP INVITE has already expired. It’s a classic race condition between the platform’s ‘Expected’ answer time and the agent’s ‘Actual’ hardware performance. Disabling power-saving mode for the agent workstations is a mandatory architect-level fix for these SIP 481 errors!
Greetings! I’m the speech analytics manager and I’ve seen these ‘Ghost Calls’ ruin our topic detection accuracy because they generate thousands of ‘Zero-Length’ transcripts! To add to the technical fixes, you should also check your ‘Load Balancer’ persistence. If you have multiple Edges and the ‘SIP Invite’ goes through Edge A but the ‘Answer ACK’ from the browser is routed to Edge B, Edge B will return a 481 because it has no record of that call! You must ensure that your network utilizes ‘Sticky Sessions’ for SIP traffic to ensure the entire transaction stays on the same physical Edge appliance. It’s a fundamental voice engineering requirement for high-availability setups!