valószínűnek tartom, mert az én böngészőmből megy. De a lényeg:
"You could either add the following to prefs.js in your profile folder
user_pref("mail.strictly_mime.parm_folding", 0);
or use Tools -> Options -> Advanced -> General -> Config Editor , type mail.strictly_mime.parm_folding in the Filter:, and then double click on the 2 and change it to 0."