Hi! Thank you for reporting this. We could reproduce the problem with a clean profile (this must be the cause why it wasn't discovered before). We're investigating the problem. Thank you for your patience.

Hi, unfortunatelly this is Mozilla's standard text now :( Either you have to wait until tomorrow when Firefox 57 will launch or you can find previous versions of the add-on under https://addons.mozilla.org/hu/firefox/addon/google-translator-for-firefox/versions/. I hope you'll find the add-on useful in your daily life.