Unable to use Advanced Security On the Go

Apple 16 pro max and it’s updated to the most recent iOS. 

@kds5114 I appreciate you clarifying that for me. Can yo please tell me if you are attempting to make this change while connected to your home network?

Yes. I am at home, connected to the home network. 

@kds5114 Thank you for providing the details that you have checked and done so far. If you could send our team a direct message with your full name, the name listed on the account (if different), and the service address associated with your account, I'd be more than happy to look into this for you.

 To send a Direct Message, please click on the “Direct Message” icon in the top-right corner of the screen, next to the bell icon, click the "New message" (pencil and paper) icon, then type or select "Xfinity Support". Type your message in the text area near the bottom of the window and press Enter to send your message and initiate a live session.