chrisdewey
Assuming you mean trusted DOMAIN rather than web site domain.
Note that sme server suports NT style DOMAINS & does not support Active Directory.
There are Windows reg entries you need to change, see
https://wiki.contribs.org/Windows_8_SupportAlso versions of that article available for Windows 7 & Windows 10.
See the Howto link at top of Forums.
Samba 4 integration for sme server is being worked on to support "some" Active Directory functionality, but it will likely be a long time before being complete & only applicable to sme 10, which is still in alpha development stage, so also some time away before release.
If the above links do not resolve your problems then you need to provide us with much more details & exact error messages, server setup details, Windows client versions etc.