When I try to log in on my mobile device, the 2-Step screen displays a blank screen/ empty box

A knowledge base article about When I try to log in on my mobile device, the 2-Step screen displays a blank screen/ empty box provided by the UC Berkeley IT Service Hub - Knowledge Portal

Content restrictions on mobile device (such as an iPad or iPhone) will interfere with the DUO 2-Step Panel, and prevent the iFrame from loading properly. Please disable parental controls or content restrictions on your device and try again.

For instructions on checking content restrictions on an iOS device, see the Duo website.

Additionally, Duo recommends these troubleshooting steps on your iOS device:

check that Javascript is enabled in the Safari settings
check that there is no ad-blocker in Safari
check that there is no installed profile/mdm/VPN that is unfamiliar
check that Screen Time restrictions are turned off
check that Focus Mode has been disabled
once content restrictions are disabled, clear browser cache

For information on how to delete history, cache and cookies on an iOS devices see this link.