The first thing you need to do before you attempt to connect to your GIS server is grant yourself administrative access to it. You do this by adding your operating system account to the agsadmin group, which contains a list of users who can administer the GIS server. If there are others in your organization that need to administer the GIS server, you can add their accounts as well.
Don't worry if you don't have the complete list of administrators; you can always add and remove accounts later. It's important to note that the accounts you add to this group will be able to add, delete, and modify services running on the GIS server.
If you've added an account to the agsadmin group, you do not need to add it to the agsusers group.
1. On the SOM machine, start the Computer Management application. Computer Management can be found in the Control Panel under Administrative Tools.
2. Expand System Tools, then Local Users and Groups, then Groups.
3. Right-click the ArcGIS Server administrators group, named agsadmin, and click Properties.
4. On the Property page, click Add and, in the dialog box that appears, add your operating system account and any other accounts to which you want to grant administrative access to the GIS server. The account you add will be the account that you typically run ArcCatalog through.
5. Repeat steps 1 through 4 on each server object container machine.
The users of the accounts you add to the ArcGIS Server administrators group may need to log off and back on before the new settings take effect.