[Samba] The network path was not found.

[Hef]

I am attempting to join a windows 7 computer running in virtual box to a
samba4 domain (version 4.1.0pre1-GIT-243278a).

I get prompted for credentials, I use the provisioned Administrator
account, and then get the following:

The Following error occured attempting to join the domain
"ad.redacted.com"

The network path was not found.


(I have replaced the actual domain with redacted for this email)

I have a ns record for ad.redacted.com pointing to the samba 4 instance,
but the samba4 server is running on a vm instance in several hundred miles
away.

What am I doing wrong? What else can I do to debug this problem?

--hef