Hello @nancyba
Welcome to the balena Forums.
We do have users who have successfully managed to flash Tails OS using balenaEtcher as reported here: Etcher successfully flashes a USB with Tails 6.4 img and validates, but doesn't boot
Please could you provide details of the Tails OS file you are using, details of the version of balenaEtcher that you are running and also post the contents of the developer console when the error has occurred? You can get to the console by pressing CTRL+SHIFT+I.
You could also try using the latest version of balenaEtcher which is available to download here: https://www.balena.io/etcher/
Regards
Mark