When configuring security in ArcGIS Server Manager on Windows 2008 R2 (IIS 7.5), navigating to either the Users or Roles pages displays the following error message:
"Unable to connect to SQL Server. Possible reasons include SQL Server not running, network problems, and permission denied for the account used to access SQL Server. See ArcGIS Server Help for more information."
This issue applies to ArcGIS Server for the Microsoft .NET Framework.
The default identity of Internet Information Services (IIS) application pools has changed to 'ApplicationPoolIdentity' in IIS 7.5. In earlier IIS versions, the default identity was 'NetworkService'.
Solution or Workaround
Create a new application pool that runs as the NetworkService identity and assign the ArcGIS Server applications to use this application pool.
Open the Internet Information Services (IIS) Manager.
Right-click the Application Pools node and select 'Add Application Pool...'.
Specify the new name as 'ArcGISApplicationsAppPool' (or a name of your choice).
In the list of Application Pools, right-click 'ArcGISApplicationsAppPool' and select Advanced Settings...
In the Advanced Settings dialog box, set the following properties:
While still in IIS Manager, navigate to the ArcGIS Server instance.
Right-click the Manager Web application and select Manage Application > Advanced Settings....
In the Advanced Settings dialog box, change the Application Pool setting to 'ArcGISApplicationsAppPool'.
Repeat Step 8 for each Web application in the instance:
KML Manager Mobile REST Security Services Tokens WMS
Close the IIS Manager.
Log in to SQL Server Management Studio.
Add 'NT AUTHORITY\NETWORK SERVICE' as a login under Security > Logins > New Login...
Under the 'User Mapping for the Network Service' account, add the following database role membership for the SQL Database that will be used to store ArcGIS Server users and roles. In this example, the database is called ArcGISServer.