Appears to be a known issue. Take a look here. Do also read the comments, especially the two links below.
Windows 10 1903 feature update breaks the client connector
https://techcommunity.microsoft.com/t5/windows-server-essentials-and/windows-10-1903-feature-update-breaks-the-client-connector/ba-p/726834
Please read the following blog posts (2 parts) to find the exact solution.
https://smulholland.me/blog/windows-update-1903-and-windows-server-connection-issues/
https://smulholland.me/blog/windows-update-1903-and-windows-server-connection-issues-part-2/