iOS and macOS have configurable content restrictions that can potentially prevent the Duo authentication prompt from displaying correctly.
If you see a gray box instead of the Duo prompt on your Apple device or the Duo prompt will not load, these content restrictions may be in place. Duo provides instructions on resolving this issue at the link below:
Article at Duo.com : How do I resolve Duo Prompt display issues related to iOS or macOS content restrictions?
The instructions for macOS Ventura and above have not yet been added in that article. Please follow the instructions below if you're running macOS Ventura or higher:
1. Open System Settings.
2. Navigate to Screen Time>Content & Privacy>Web Content.
3. Set Access to Web Content to Unrestricted Access or turn it off completely.
If you do not want to allow unrestricted access or turn off the web content restriction feature, you can click Customize, then add duosecurity.com to the Allowed Websites list instead.
If you are still having trouble getting the Duo prompt to display on your Apple device, please contact the Service Desk at servicedesk@msstate.edu, 662-325-0631, or put in a ticket using the Request assistance with Two-Factor Authentication service.