I am only able to send an email by opening Thunderbird and selecting write. If I try to attach a file by starting with the file > send to > mail recipient or try to trigger Thunderbird with an email address in a browser or start with a distribution list in the address book, all fail. All produce the following diagnostic: "Sending of the message failed. The message could not be sent because connecting to Outgoing server (SMTP) localhost failed. The server may be unavailable or is refusing SMTP connections. Please verify that your outgoing server (SMTP) settings are correct and try again."