Ran into the same problem today, tried all the solutions in this tread and then some, but none worked.
I could access the shares from other computers running the exact same windows version.
Then i remembered at one point i tried to login to a (sub) share with different credentials, which turns out was the reason for windows not being able to access my Unraid server any more.
The solution turned out to be quite simple
Go to control panel -> User accounts -> windows references and delete all entries to your server (both IP and name) and you're good to go.
(windows references might be called something else as i'm translating it from a Dutch windows version)
Just posting this here in case someone else has the same issues