The image of the QR code is unavailable when setting up 2-factor authentication via the Authenticator App option, on the Profile page. Google Charts API QR code generation is no longer available. When adding MFA, the QR code image does not display. The request to the Google Charts API returns a 404. Here's a related thread on this: https://groups.google.com/g/google-visualization-api/c/J-V7alUJVVc?pli=1