Microsoft Remote Desktop Mac client not working after upgrade to 10.8.0 error 0x3000064

Hi aureliendcsystems emoy88 RBT05 Roman_Mondek jazar01 and all,

We have triaged an issue and working on a fix! When connecting to an on-prem deployment gateway, the client by default will try to connect via WebSocket first. If the gateway doesn’t support WebSocket then the client will fall back to using plain https channel. Based on logs from users experiencing these error codes on 10.8.0, the issue seems to be happening during WebSocket connection where the client did not fallback properly to https channel and instead thows the error. 

The current options are:

1. As previously mentioned, download the last stable beta Version 10.7.9 (2011) from here: https://nam06.safelinks.protection.outlook.com/?url=http%3A%2F%2Faka.ms%2Frdmacbeta&data=05%7C01%7Crdios%40microsoft.com%7Cbda77ca204e246714d8f08dae261163a%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638071203891715197%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=YFvNHTdKLnJOIpt7%2FtyOFr2Rhj1oHt0PTCoFFISESH8%3D&reserved=0 (As the app store doesn’t allow you to downgrade)
2. If you want to stick with 10.8.0 from the Appstore, type this in the Terminal:
   defaults write com.microsoft.rdc.macos ClientSettings.DisableOnPremWebSocketGateway true. 
   The setting bypasses the WebSocket connection attempt and simply connect with plain https channels. Note: Performance-wise WebSocket is expected to be faster than https channels.For deployment en-masse, if you can push policies to the managed macs, we would suggest this option (after verifying it works on your mac). However, if these are not managed macs, then we would suggest option (1) and waiting for an official fix to be pushed to the Appstore (likely after the new year).

Thanks