There was much shouting this morning when I realised that all of my RDP sessions were failing due to a pesky little error. They worked no problem at all yesterday, then I remembered .. windows updated last night!!
Said error was all but useless .. as everyone knows you can’t copy the url it shows in that dialog box.
A quick google resolved this with a very simple reg change.
reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters" /f /v AllowEncryptionOracle /t REG_DWORD /d 2
I ran this with elevated privilege on my Windows 10 desktop and as if by magic I can now RDP again.
There are more fixes coming both Client and Server to resolve this, but the reg change will keep me going until Microsoft release those.