Server 2016 Administrative Share Issue C$

I have a new Server 2016 Hyper-V vm joined to the domain. I was able to ping it, etc. Static IP with DNS all set but no matter what I did I couldn’t access the admin shares (C$, E$) with my domain admin account. 

After about 4 hours of trying all these rando tips I came across an article that recommended this:

• Login with local admin account
• Go to Sharing->Advanced Sharing and tick the box to share the drive
• Now try to access \servername\C$
• If it still fails create the following Registry entry:

Key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
Value: LocalAccountTokenFilterPolicy
Data: 1 (to disable, 0 enables filtering) 
Type: REG_DWORD (32-bit)

Now try to access \\servername\C$

If it works go back to Sharing->Advanced Sharing and un-tick the box (then test again). It worked for me.