FastMail: Unable to Send Emails — Two-Step Authentication Fix

<h2>Problem</h2><p>You've added your FastMail account to Airmail but can't send emails. You may see authentication errors or the emails stay stuck in the Outbox.</p><h2>Solution</h2><p>If you have <strong>Two-Step Verification (2FA)</strong> enabled on your FastMail account, you need to create an <strong>App Password</strong> specifically for Airmail.</p><h3>How to Create a FastMail App Password</h3><ol><li>Log into <strong>FastMail</strong> via web browser (fastmail.com)</li><li>Go to <strong>Settings → Privacy & Security → Integrations</strong> (or Settings → Password & Security)</li><li>Under <strong>App Passwords</strong> or <strong>Third-party apps</strong>, click <strong>New App Password</strong></li><li>Give it a name like "Airmail"</li><li>Copy the generated password</li></ol><h3>Update Airmail with the App Password</h3><ol><li>Open Airmail</li><li>Go to <strong>Settings → Accounts</strong></li><li>Select your FastMail account</li><li>Replace your regular password with the <strong>App Password</strong> you just generated</li><li>Save and test sending an email</li></ol><h3>IMAP/SMTP Settings for FastMail</h3><p>If needed, use these manual settings:</p><ul><li><strong>IMAP</strong>: imap.fastmail.com, Port 993, SSL</li><li><strong>SMTP</strong>: smtp.fastmail.com, Port 465, SSL</li></ul>

Updated on: 03/28/2026