The Configure Authentication window of the Add Servers wizard allows you to select the authentication credentials SQL Diagnostic Manager uses when collecting performance and statistics information from your SQL Server instances. You can also set encryption to secure the connection.
After selecting a connection type and encryption, click Next to continue.
Access the Add Servers wizard
You can open the Add Servers wizard from the SQL Diagnostic Manager Console menu by selecting 
> Manage Servers and clicking Add in the Manage Servers window.
Select a connection type
Windows Authentication is the recommended collection type as SQL Diagnostic Manager uses many SQL trace statements that require a trusted connection. When you select and use Windows Authentication, the account the SQLdm Collection Service is running as is used to connect to the SQL Server instance.
From SQL Diagnostic Manager 12.0, you can monitor across untrusted domains by selecting the Alternative windows domain/user authorization.
Select encryption
SQL Diagnostic Manager allows you to designate encryption methods used to encrypt data between the SQLdm Collection Service and the monitored SQL Server instance:
- Encrypt Connection.
- Trust Server Certificate (Bypass Certificate Validation): Only available after you select Encrypt Connection.