Windows Server 2012 R2, cannot install any role or features using GUI Server manager

Exiting environment : Windows Server 2008 R2.
I am in the process of migrating to Windows Server 2012 R2. I installed Windows Server 2012 R2 on HP DL380p G8 server. I am able to install role or feature using PowerShell but not via GUI ServerManager.

Now, when I go to add a any role or features using GUI ServerManager I am getting the following errors:

**Failed to open runspace pool. The Server Manager WinRM plug-in might be corrupt or missing**

I did the following troubleshooting already:

• Run WinRM quickconfig which shows the service is running and setup for management.
• Restored WinRM settings: winrm invoke restore winrm/config @{}
• Restored WinRM plugin settings: winrm invoke restore winrm/config/plugin @{}
• Add "127.0.0.1" and "::1" to the IP listen list
• Disabled the firewall
• Ensured the Windows Remote Management (WS-Management) service is running.
• Granted the “Validated Write to Service Principal Name” permission to the NETWORK SERVICE using theADSIEDIT.msc

Following are the errors logged:
Event ID 10154

The WinrRM failed to create the following SPNs:WSMAN/xxx.abc.com:WSMAN/xxx

Application and services log
Event ID 142

WSMAN Operation CreateShell failed, error code 2150858811

I googled but nothing seems to help.

Any help will be highly appreciated.