Windows 7 Client to OSX Server 5 (Password Error)
I assume the OS X Server is not integrated in your AD environment. Then all credentials (user name/password) have to be set up on the OS X Server - at least as network account. Additionally all OS X Server shares have to be set up properly.

Then you have to enter the IP address and the name of the share (e.g. \\10.10.1.12\Data-User1).

The proper credentials in the Windows Security dialog are then: the user name and the user password (e.g. User1 and Passw0rd).

server\User1 only works if the OS X server is part of Active Directory and has the fully qualified domain name server.sld.tld (or in your case server.unionsupply.net).



server.local is no domain name but a qualified mDNS name in the link-local domain .local. This isn't intergrated in a common DNS environment.