If you are getting an error message saying ‘Window Blocked’ when using a Trezor, Ledger, or MetaMask to confirm a transaction, this is because you are blocking pop-ups with the browser.

To fix this issue, you will need to ‘Allow Pop-Ups’ for MyEtherWallet.com.

This allows information to be sent safely to your device/extension so that the transaction can be signed and transmitted on the blockchain.