How do I remove AirPods 3rd Gen from Apple Account for resale?

I’m in the process of selling my airpods, so I’ve forgotten them from my device and removed them from my apple account, but when the person who wants to buy is trying to connect them to her phone, it’s saying they’re still connected to my apple account and that I need to sign in and remove them, which I’ve already done and once I sign in and go to devices, they’re no longer listed under my devices but still shows they’re connect to my email when she’s trying to connect. What do I do?

[Re-Titled by Moderator]