Give domain user access to files on app server

It’s been a while since I’ve dabbled in security access. I’m attempting to move some users’ home drives to another server because we’re running out of space on our DC. I created a HOME share on the other server, created a folder for a user under it and gave their domain user object mrlrw access to this folder. When I log on as them, I can see it but cannot save files to it. Does this server need to be added to the domain somehow as trusted?

Both servers are 2003 / AD environment.

Any help or a point in a place for the answer would be appreciated.

Thanks.