How to Fix: SMTP Error (535): Authentication Failed?
SMTP Authentication is the process by which an ISP’s clients authenticate themselves with the mail server to which they intend to send an email. It is not possible for anyone to send email via any mail server; mail servers will only allow legitimate users to send an email. How it operates: When a user sends an email, the user’s mail client (Outlook, Outlook Express, Thunderbird, etc.) authenticates itself to the mail server by providing the