.Net WinForm - Web Browser control navigation results in 'Navigation to the webpage was canceled'

Hi,

Version:  Adobe Acrobat Standard DC

Windows: Windows 7 Enterprise 64 bit

Adobe Acrobat Config: Protected View - off, Enable Enhanced Security - off

I have an WinForm application using a Web Browser control to navigate to PDF files in the local drive.  The Web Browser is embedded in a WinForm.  When I call the method Navigate(), the 'Navigation to the webpage was canceled' message appears in the web browser control and a separate Adobe Acrobat Standard DC window is popped up showing the PDF.  The same application works in Windows 10 64 bit.  Any help would be much appreciated.

Thanks