This is tough for me to describe so I'll give it a shot. Ever since the July 24th update (July 24, 2018—KB4340917) I have not been able to connect to to any remote desktop host by name. It works by IP address but not by the host's name.
I get the usual "Remote Desktop can't find the computer "DavidsPC". This might mean that "DavidsPC" does not belong..." etc etc.
Note, I am able to connect to this remote computer using mobile devices (Android and iPhone) without a problem.
In researching the problem I found lots of posts about KB4103721 however I do not have that particular update installed on my computer.
Thoughts?
mr.smith