Aspose PDF Flatten not working

Hi,

I am using Aspose PDF dll to flatten my fillable pdf's and its not working.

My actual requirement is to concatenate two pdf's. When i am trying to concatenate a fillable pdf with normal pdf it is not concatenating hence i thought of flatten the fillable pdf and concatenate them.

Aspose.Pdf.Facades.Form pdfForm = new Aspose.Pdf.Facades.Form("input.pdf", "HelloWorldOutputConv1.pdf");
pdfForm.FlattenAllFields();
pdfForm.Save();

I am using Aspose.pdf version 7.1.0.0 Aspose.pdf.kit 5.4.0.0

Any help will be appreciated.

Thanks in advance..