Worked before, but they were on a >10 year old laptop, Win7, hence my CWA compatibility question in #CL7B5GFHR yesterday. They went and got a new laptop yesterday as that was their final push to get a new one.
No Optimal Gateway Routing for on-prem. Also figured I eliminated on-prem config/misconfig, with the exception of VDA and CC->VDA by having them try Gateway Service.