Windows 7 User from another domain cannot access our NAS Server using Windows 7

[freakyboy2003]

Hi. We have a domain (let's say, Domain1) and a NAS Server. This NAS Server uses Windows Active Directory to authenticate user access. Everybody using Windows 7 and MAC can access the NAS Server using their Windows password. We have another branch in another country (let's say, Domain2). That user is visiting our country and office, and needs access to the NAS Server. That user is already joined to Domain2. I tried connecting to our NAS Server using my credentials (and other user credentials from Domain1), but Windows 7 kept asking for the password. How do I connect the user from another domain to our NAS Server using Windows 7? Thanks.

 

[freakyboy2003]

Just wanted to add..... the user from domain2 is connected to our domain (domain1) through our LAN and can access the internet.