Sometime you may get below error message when you try to open SQL Server Configuration Manager.
Cannot connect to WMI provider. You do not have permission or the server is unreachable. Note that you can only manage SQL Server 2005 and later servers with SQL Server Configuration Manager Access denied [0x80070005]
It may be possible that permissions to your account is messed up at OS level. Try to remove account from local admin group, delete the current profile for the user in the server. Reboot your box. The above issue will be resolved.