Upon trying to enable remote command execution using PSExec, I ran into an issue trying to login with a local administrator account on my remote server: Access is denied.
Apparently, if you have an account that's a local Administrator, Remote UAC will block them from being able to do things like remote execution.
A quick way to test if this might be your issue:
To get around this, you can make a registry change:
You should be able to execute remote commands.
Solution found via Admin Arsenal Support: Can't access the ADMIN$ using a local user account.