Problem sending email messages

It's in "SETTINGS" ---- "PRIVACY & SECURITY".

Thank you. Have followed your advice above and my password is correct. However when I try to send, I get "Login to server mail.btinternet.com with username carolofdawes@btinternet.com failed". this gives me the options "Retry, enter new password, or Cancel." REtry results in message "Sending of the message failed. Unable to authenticate to Outgoing server (SMTP) invalid user ID or password. Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)'." Enter new password - I enter my (correct) password and get: "invalid user ID or password. Please verify that your email address is correct in your account settings and try again." Or then again, the system will suddenly start working again and I can send emails, as it did just now when I was testing it out. Problem then comes back the next day! Do you have any further advice please? Best Carol

That same error message will come up if your antivirus blocks the connection. It is a generic catch all error for failure to connect. More specific information can frequently be found in the error console (ctrl+shift+J) but it is not in a user friendly form and you really need to post the error message to get someone to interpret it, if they can.

My suggestion if open the error console, use the mouse to clear it using the trash icon on its toolbar and then undertake the action that is failing and see what message appears. The console has loads of rubbish in it that just muddy the water. Note that there is a right click menu to copy so you can paste into your reply message on this topic..