Using a samba server is a good idea as it is both considered the overall best option, and also will allow cross-compatibility with your windows systems.
the syntax for rclone should be just the same as any other copy operation to that server, so I kind of suspect this is a server configuration issue rather than an rclone problem.
Have you verified that you can copy to the server normally? (like in the desktop GUI, or from a simple copy command in the terminal).
Also, what user account is rclone running as? If you launch it as a system service or something of that nature then you might be using another user-account then your own personal one - and if that is the case you need to make sure that this account also has write permissions to the server.
Finally - if you want to see if you can get some more spesific info out of rclone then try adding these two flags to your copy command before you run it:
Then you can share this file with us for analysis (it will contain a lot more info than normal output and thus hopefully show the underlying problem). You may need to post it on pastebin.com if it is very long. Some names of files and folders may be exposed in the log, but otherwise there should be little security risk associated with sharing the log. If you don't want to share it publicly you can alternatively PM me, but then you might miss out on responses from others who want to try to help you.