Join your Mac to a network account server
If you join your Mac to a network account server, you can use services such as contacts, calendar, mail, instant messaging, and more. You access these services using Contacts, Calendar, Mail, Messages, and other apps on your Mac.
To make sure you join the appropriate server, ask your network account server administrator for assistance.
Connect to a network account server
On your Mac, choose Apple menu
, then click Login Options.Open the Login Options pane for me
If the lock at the bottom left is locked
, click it to unlock the preference pane.Click the button next to Network Account Server.
The button is labeled Join if you haven’t already connected to a network account server. It’s labeled Edit if you already have an existing connection.
If you clicked Edit, click the Add button
.Enter the fully qualified domain name of a network account server in the Server field, or choose one from the Server list, then click OK.
To add another server connection, click the Add button
, then repeat step 4.You can join one or more network account servers.
Click Done.
If your computer name contains a hyphen (-), you might not be able to join a network account server. To check your computer name, and change it if necessary, use Sharing preferences.
Choose Apple menu > System Preferences, then click Sharing 
.
Stop using a network account server
On your Mac, choose Apple menu
Open the Login Options pane for me
If the lock at the bottom left is locked
, click it to unlock the preference pane.Click Edit.
Select the server you want to stop using, then click the Remove button
.Click Stop Using Server, then click Done.
Monitor network account servers
On your Mac, choose Apple menu
Open the Login Options pane for me
If the lock at the bottom left is locked
, click it to unlock the preference pane.Click Edit.
Note the color of the dot to the left of each server name in the list:
Green: The server connection is working.
Yellow: Your computer is waiting for a response from the server.
Red: Your computer isn’t connected to the server.
To use most network services, you need a user account on the server that provides the services. The server can have its own user accounts, or it can use network user accounts. On a network with multiple servers, all servers usually use the same network user accounts, which are provided by a network account server, sometimes called a directory server.