I think there might be a few more things to check:
User limitation of the smb Protocol= It can only be used one user per Win workstation. So if there is already a connect (net drive) with another username open it will fail to connect with a different user.
Second thing is then configuration of Samba. If this uses the old CIFS protocol, then this must explecitely activated on Win 10 ( install programs -> add additional features-> Serch for CIFS or SMB 1.0 protocol.