SUDDENLY, Thunderbird won't allow me to blind copy to the people on my email list sent out from my aol email. My SMPT set up is FINE; it has never changed. It has NOTHING to do with 'adding semicolons" between addresses; I have NEVER had to do that before; please don't suggest that now. message: "Sending message failed. An error occurred while sending email. The mail server responded: error sending message for delivery..Please check message and try again." It happens with 2, it happens with 10, it happens with 25 or 40 recipients.