Not sure if this will get posted twice, if so appologies. I have used Thunderbird with my BT mail account for about 10 years. Just this week I've been getting this message: The mail server responded: Too many messages. Please check the message and try again. Sometimes the message is sent anyway, sometimes not. BT technical support are denying all responsibility and saying it is a Thunderbird fault, I am fairly sure it isn't but don't know how to fix it, any ideas anyone?