Always throws a NotSupportedException.
Public Overrides Property UseDefaultCredentials As Boolean
Default credentials are not supported for FTP.
The UseDefaultCredentials property is provided only for compatibility with other implementations of the WebRequest and WebResponse classes. There is no reason to use UseDefaultCredentials.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.