Why am I unable to RDP to Windows 10 since virtualizing it?

This could also be related to a recent windows update. I recently updated to 2004 to be able to run WSL2. When I virtualized the machine I followed the recommended Oracle Virtual box steps, which included running a script to remove the disk adapter drivers. then I imaged the disk over to a VMDK. Everything on the machine runs fine, there are the occasional bugs, that don't seem related to this.

When I RDP in I get the error message below.

I have found several error messages in the Event Viewer on the Remote Machine. All of the interesting ones seem to be under RemoteDesktopServices-RdpCoreTS. Here are some of the more interesting ones in order.

1. 'Failed GetConnectionProperty' in CUMRDPConnection::QueryProperty at 3344 err=[0x80004001]
2. 'Connection doesn't support logon error redirector' in CUMRDPConnection::GetLogonErrorRedirector at 4657 err=[0x80004001]
3. 'Failed GetConnectionProperty' in CUMRDPConnection::QueryProperty at 3344 err=[0x80004001]
4. Disconnect trace:CUMRDPConnection Disconnect trace:'calling spGfxPlugin->PreDisconnect()' in CUMRDPConnection::PreDisconnect at 5073 err=[0x12], Error code:0x12
5. TCP socket WRITE operation failed, error 64
6. TCP socket READ operation failed, error 64

Here are some of the things I have attempted so far.

• Confirmed IP Address
• Disabled Firewall Attempted to disable RemoteFX via GPO https://serverfault.com/q/886027/95189 then
• attempted to disable it via Registry. Added and then removed
  • Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\fEnableRemoteFXAdvancedRemoteApp with 0x00000000
• Attempted to increase the Max Outstanding Connections
  • https://serverfault.com/a/940808/95189
• Changed RDP host hostname
  • Some research indicated something about cloning machines could confuse the network.
• Install VirtualBox Extension Pack
  • Running 6.1.6 on everything
  • 6.1.10 seems to be the latest via Oracle, but with the Ubuntu repos 6.1.6 seems to be what they have available.
• Disabled Nested VT-x/AMD-V
  • Something about RemoteFX requiring this feature, so I attempted to disable RemoteFX by removing its requirement.
• Disable URCP
  • https://itcalls.net/windows-10-version-1809-black-screen-when-connecting-rdp-to-server-2019/
• Attempt to update Hyper-V Virtual Machine Bus Provider but it failed.

We noticed we had installed a VPN client on our Windows Server 2016 (Netmotion) which was also having a problem loading. Uninstalled netmotion and problem solved.

but I had also applied the registry entry you mentioned above.

so which one fixed it? don't know, but we can now RDP into our server.