Use this guide to spend from Electrum cold storage: https://electrum.readthedocs.io/en/latest/coldstorage.html

Do not use QR code but use copy/paste or transfer using file or so. You may not like this which is the reason you use Tails OS but Electrum can give such error while using QR code for signing on a cold wallet.

Use this guide to spend from Electrum cold storage: https://electrum.readthedocs.io/en/latest/coldstorage.html

Do not use QR code but use copy/paste or transfer using file or so.