Sharing is more dependable if every machine on the network has a credential built in credential manager for each of the other networked machines.

1. Open the Credentials Manager from the Windows Control Panel.
2. Go to Windows Credentials.
3. Click Add a Windows credential.
4. In the "Internet or network address" field, enter \ followed by the computer name or IP address of the computer sharing files or printers.
5. Enter the username and password for an administrator account for the machine you are trying to access. For example I network 4 computers. In each computer I created a credential for the other 3.

Note: Even if computers use the same user account name and password, even the same MS account, you still need to create a credential for it.

It must be a password, not a pin. While you can still use a pin to log in, you must restart the device and log into it using a password at least once for this to work.