When I try get a HasOpenPassword property from Aspose.Pdf.Facades.PdfFileInfo an NullReferenceException is thrown

A Pdf-file is exists and AsposePdf.Facades.PdfFileInfo is not null. But When I try get a HasOpenPassword property an exception is thrown:
System.NullReferenceException: PdfFileInfo is not initialized. Use constructors with parameters or properties for initialization. (File: C:\Users\dpr\AppData\Local\Temp\Workshare\mi5bhr41.2wc\1\16680848_1_HN12990 - title plan.PDF) (Reason: Object reference not set to an instance of an object.)
   at Aspose.Pdf.Facades.PdfFileInfo.AssertDocument()
   at Aspose.Pdf.Facades.PdfFileInfo.get_IsEncrypted()
   at Aspose.Pdf.Facades.PdfFileInfo.get_PasswordType()
   at Aspose.Pdf.Facades.PdfFileInfo.get_HasOpenPassword()

What do you think about it?