I can connect to Thunderbird and receive email. However, I cannot send emails. When I press send (either from replying to an email or entering an email address manually) I get the following error message: Sending of message failed. No sender specified. Please fill in your email address in the Mail & Newsgroup Account settings. When I click on the menu option within the email message Tools/Mail & Newsgroup, the message minimises and the programme returns me to my inbox. There is no Mail & Newsgroup setting on the mail programme.