Here is a Windows Server 2012 Server Manager troubleshooting guide:

Here is a Windows Server 2012 Server Manager troubleshooting guide:

Windows Server 2012 - Server Manager Trouleshooting Guide: Part I Overview

Windows Serve 2012 - Server Manager Troubleshooting Guide: Part II Troubleshooting Manageability Statu Erros in Server Manager

Windows Server 2012 - Server Manager Troubleshooting Guide: Part III Common Events and Errors in Server Manager