Some Windows 10 versions have a default setting which prevents logon to remote servers. To fix this you have to enable insecure guest logons:
1. Open the Local Group Policy Editor (gpedit.msc).
2. In the console tree, select Computer Configuration > Administrative Templates > Network > Lanman Workstation.
3. For the setting, right-click Enable insecure guest logons and select Edit.
4. Select Enabled and select OK.