I have very successfully got the PDF viewer to work with PDF files stored on Azure Blob Storage.
It works very well when the PwerApp is opened in the desktop PowerApps Studio, but it will not show the PDFs when the PowerApp is opened in the browser.
I have tried Chrome, Edge and even Explorer.
PS I use SAS tokens for authentication
Please vote for this idea
I can reproduce this issue. The PDF could show in my Windows studio but won't show in IE.
It seems that it is true that PDF viewer is not supported in web browser now.
This may be an issue with CORS? Or not?
I have managed to show some pdf in the browser, like this:
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