Error while opening the Windows Defender in Windows Server 2016

This may be a problem with the local security policy. It can be easily changed.

Access the local security policy GUI by gpedit.msc into cmd or run. If that doesn't work you can go to Server Manager --> Tools --> Group Policy Management`

Once your there go to

Computer Configuration-> Windows Settings-> Security Settings -> Local Policies-> Security Options

then enable the policy that says "User Account Control: Admin Approval Mode for the Built-in Administrator account"

Once you do this, you must restart