Ledger recently released an update for their Bitcoin app that causes Green to not recognize your Ledger Nano device. We recommend you to use instead the Bitcoin Legacy app on your Nano device:

1. In Ledger Live, go to Settings > Experimental Features > Developer mode and toggle it ON. This enables you to download the Bitcoin Legacy app.
2. Go to My Ledger > Connect your Ledger Nano S or X device > Allow Ledger Manager on your device > Search for "Bitcoin Legacy" and Install it. You might need to delete other apps currently on your Ledger device if you have no available space, which you can do with peace of mind. Removing an app is not a risk for your funds, you can re-install it later on.
3. From now on, when using your Ledger Nano S or X with Green, simply open the "Bitcoin Legacy" app on your device.