It’s not clear whether you’re trying to connect with public key, or mapping ssh port. In any case, the best thing for you to do is send us the logs from the non-working Windows server (the one you are not able to connect to). Follow the instructions here and then send them to forum[at]nomachine[dot]com making sure you reference the title of the topic in the subject of your email.https://www.nomachine.com/DT10O00163#1.
Then from the client side, either the RPi4 or the working Windows host, send us the .nx folder. https://www.nomachine.com/DT10O00163#2.