Hi Greg,
This happens because Microsoft blocks some IP ranges from downloading the ISO directly. As a workaround, please use the Media Creation Tool to download the ISO. You can download the Windows 11 Media Creation Tool (MCT) from this link:
https://go.microsoft.com/fwlink/?linkid=2156295
Run MCT and choose the ISO option when prompted.
If that doesn't help, let me know so I can generate the direct download link for the ISO.