check SMTP server settings Tools > Account Settings > Outgoing Server (SMTP) * Outgoing SMTP server name: outgoing.yahoo.verizon.net * Port: 465 * Connection Security: SSL/TLS * Authentication method: Normal password re: "login to server outgoing.yahoo.verizon.net failed" Was that the full and total error message? Was there is a bit more info. Can you send a single email on it's own? Is it only when you want to send a list? Tell me about this 'list': Have you created a 'Mailing List' as a sub list of an address book - are you using this 'list'? or do you just add a load of email addresses into Bcc fields? Is at least one of those in a TO filed?