Can anyone explain why the WebRTC handshake is failing with a 408 timeout specifically for agents in the UK-East region? The genesys-cloud-sdk-js v2.6.1 client logs show the offer is sent, but the answer never arrives before the 5-second threshold. The WebRTC Configuration Guide suggests checking STUN servers, but our firewall rules are open and identical to the US-East setup which works fine.