You must provide specific permissions for users to access WebDAV shared storage.
In Microsoft Internet Information Services Manager (IIS), select your WebDAV folder and click Authoring Rule.
Under Permissions, select the checkboxes for Read, Source, and Write, and click OK.
Authentication type
Configure the type of permitted authentication in Microsoft Internet Information Services (IIS).
In Microsoft Internet Information Services Manager (IIS), select your WebDAV folder and click Authentication.
From the authentication list, select Password based Authentication.
In the Actions menu on the right, click Providers.
Select the type of authentication and click Add.
Note
Select Negotiate if you want to use Kerberos authentication.