tlicht
....domain controller.....so no big problem/harm...
I am the only user and there are only 5 - 9 computers/devices on the LAN.
All your DOMAIN login machine accounts will have to be recreated ie workstations will need to rejoin the DOMAIN & you will need to create new user profiles for each user on each workstation, is that not a problem for you ?
....Actually just now not even the smtp server seems to manage to send mails...
It seems you are a new sme8.x user.
I strongly suggest you read the release notes for sme8.0 & sme 8.1, they are in the Announcements forums.
There are settings in server manager for smtp proxy that IIRC are different to sme7.
Also you would (may) typically need to enter your ISP's smtp server address in the Email section of server manager.
You should for security reasons (in my opinion) or may also need to configure sme server & your workstation email clients to use ONLY secure connections, again refer to server manager Email panel.
It all depends on what else is in your network (routers. firewalls etc) & whether your sme server is a gateway server with a bridged modem in front of it, or if you have some other network arrangement for access to the Internet etc.
There is no reason (typically speaking) why smtp access should not work, other than incorrect or inappropriate configuration.