I have tested this and found that although this code works with other websites but has problems with microsoft website. I have logged this as PDFNET-4609 in our issue tracking system. We will try our best to figure out the cause of this problem and try to rectify it as soon as possible.
Both generate argument exceptions when used in the above code. I imagine there are sometimes objects in web pages that can’t easily be converted to PDF but I would have expected some kind of placeholder instead of an exception.