Have you accepted the warning on Ledger device IOTA app?
If you see the warning for a split second but don't have a chance to confirm it on the Ledger, some program (like Trinity, Ledger Live, Browser) is running and accessing the ledger device. Close everything and try again.
If the warning message still disappears, you can try the following to be absolutely sure that nothing is interacting with the Ledger:
- Plug the Ledger device into a USB charger e.g. for your phone. Anything that is not a computer.
- Enter your PIN and then start the IOTA application. You now see ‘WARNING!’
- Scroll through the warning and accept it. To do so, press the right button 5 times until you see ‘for more info’ and two horizontal lines where the buttons are. Press both buttons at the same time to show ‘IOTA’.