And if you map a network drive using your B2's IP address and the sharename "music", e.g.:
(put YOUR B2's IP address where I've put mine in the picture)
does that eventually bring up a box asking for the username and password to use? (NOTE the checkbox "Connect using different credentials".)
The B2 is slow, by the way -- this could easily time out and fail the first time you try it. I'd try it twice just to be sure it's really failing and not simply being slow to connect.