Hi Russell
Usually the part that trips people up in running some of the Genesys test tools is they're hosted on port 8080 for some reason which at a lot of organisations isn't allowed. What you might want to consider also doing is turning on logging for one of these users for a day and look for WebRTC issues/errors. Another one which I use quite frequently is the webrtc-internals tool in Chrome which gives you a bit more visibility of what's trying to happen during WebRTC negotiation.
It's also worth a double check of the CIDRs that have been allowed for the media layer based on your region.
Lastly, don't rule out something as simple as a microphone permissions/exclusivity issue with a headset - or even being plugged into the wrong port if it's an old school 3.5mm wired headset. Some workstations out there have two headset ports but one is really just headphones only. The main difference is the number of "poles" in use.
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Vaun McCarthyVaun McCarthy
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