c# download pdf from web link to file, access problem ?

Question

Developing a C# .net7 program and need to download a PDF from a link in a website. A specific example is this link that allows one to view a Toyota owners manual in their browser:

https://assets.sia.toyota.com/publications/en/om-s/OM12G79U/pdf/OM12G79U.pdf

I can load this in a browser (either edge or chrome) and select to download it and I can download a large .pdf file. However when I try to open that file in Adobe Acrobat it runs Acrobat but with no text visible. Windows considers Acrobat to be running and claiming ownership of the file, but nothing is displayed. No message about what is going on. I have unblocked the downloaded file.

I don’t know whether the problem is with the file, or with the way the link is designed to work. I’m guessing I could write C# code to download the file but I assume I wouldn’t be able to access it. Can anyone explain what causes this?