DJI "real-name registration not performed" warning

A "real-name registration not performed" warning in DJI Fly means the app thinks your drone or account is missing operator registration details that local rules require. DJI hasn't published a public article on this exact message, and it isn't part of the US FAA process, where you register online at FAADroneZone and don't load anything into the app. If you see it in the US, check that DJI Fly, your account and the drone are all set to the US region and up to date, then contact DJI support.

Registration warning: what to do — Registration rules depend on where you fly. In the EU, DJI's manuals describe uploading the operator registration number in DJI Fly; the FAA uses FAADroneZone instead.

What "registration" means in each region

United States. The FAA requires registration for recreational drones of 250 g or more and every drone flown under Part 107. It costs $5, lasts three years, and is done at FAADroneZone. You mark the number on the outside of the drone. Your registration must also include the drone's Remote ID serial number. Nothing is entered into DJI Fly. See FAA registration.
EU and EASA countries. Operators register with their national authority and get an operator registration number. DJI's manuals describe uploading it to the drone for Direct Remote ID: in DJI Fly, Safety > UAS Remote Identification, then upload the UAS Operator Registration Number.
Other countries. Rules vary. Some countries require the owner's real name to be linked to the drone. Check the national aviation authority before you fly. See drone laws by country.

DJI Avata 2

The Avata 2 is set up through the goggles, so the menus are reached from DJI Fly on a phone connected to the goggles. DJI's Avata 2 manual says: connect the goggles to the mobile device, launch DJI Fly, then go to System Settings > Safety > UAS Remote Identification to upload the operator registration number. Use this if you fly where that number is required, such as the EU.

What to try in the US

Update everything. Update DJI Fly, the drone, the goggles and the controller. See how to update DJI firmware.
Check your DJI account is signed in and the drone is bound to it.
Allow location access for DJI Fly. It uses your location for GEO zones and Remote ID.
Ask where the drone came from. A drone bought outside the US may be set up for a different market. DJI support can tell you what applies to your serial number.
Contact DJI support with a screenshot of the warning.

Don't skip the real requirements

Whatever the app says, the legal requirements still apply. In the US: register if required, carry proof, pass the free TRUST test for recreational flying, and make sure Remote ID is working on any drone that must be registered.