Get this error when I tried to access one of the shared folders in my network. I was running on a newly installed Windows 10 Enterprise. Made a quick google on the error as I was very sure it must has something to do with the OS’s policy. And yes it was.
So the next thing to do is open the Local Group Policy Editor by typing gpedit.msc at the Run window.
Navigate to Computer Configuration -> Administrative Templates -> Network -> Lanman Workstation and select the Enable insecure guest logons.
By default it was not configured or disabled. Click enable.
And now try to access it again. Good luck.