Safari cannot open the desktop app because it doesn't recognize the webpage that begins with aam:.

I have a Mac running msOs Big Sur 11.2.2.  I try to download the desktop app to my computer and I get the message 'failed to open' because it cannot find the page with an address starting with aam:. 

Is there a way to fix this?  I'll cancel the membership because I want the desktop app, not just the Cloud.