Open the Local Group Policy Editor on the machine you are running the Remote Desktop client.
Computer Configuration>Administrative Templates>Windows Components>Remote Desktop Services?Remote Desktop Connection Client
Enable the setting called
Turn Off UDP On Client
Now I'm able to connect without issue... somehow UDP isn't making it through and this change fixes the problem!
Should anyone wish to change the setting from registry rather than through group policy, here's the place to do that:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services\Client
fClientDisableUDP (REG_DWORD) to
PS> Set-ItemProperty -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services\Client' -Name fClientDisableUDP -Value 1