This message, which comes from the server, usually means that you are using an smtp server provided for use with one particular account to send messages "from" other accounts. The fact that it also happens with your phone does indicate that it is external to Thunderbird.

How many different email accounts do you have? How many different providers are involved?

Thanks Zenos for your reply, Yes it is thru SMTP server and 2 email accounts added, have not changed any setting. The problem started suddenly today. I have uninstalled and re-installed TB, it helped for sometime and i was able to send few emails before problem started again. Do you feel that adding more than 1 account could be the reason. Thanks again,

Please post info: In thunderbird: Help > troubleshooting Information click on 'copy text to clipboard' paste info into this question. Delete/remove all section on fonts and printers but nothing else.