SMTP Authentication Failed Error 535 occurs when the mail server rejects authentication credentials during the sending process. This means the username, password, or authentication settings provided by the email client or application are incorrect or incomplete.
This is one of the most common SMTP errors and is usually caused by misconfigured outgoing mail settings. This guide explains how to resolve SMTP Error 535 when sending email through Domains.co.za servers.
TABLE OF CONTENTS
How to Resolve SMTP Authentication Failed Error 535
1. Open the error message and confirm it references SMTP Error 535.
2. Verify that the email account password is correct.
3. Ensure the full email address is entered as the username.
4. Open your email application’s account settings.
5. Confirm SMTP authentication is enabled.
6. Verify the outgoing server name matches Domains.co.za settings.
7. Enable SSL/TLS encryption for outgoing mail.
8. Set the SMTP port to 465.
9. Save all changes and restart the email application.
10. Send a test email to confirm successful authentication.
Additional Information
- SMTP Error 535 is almost always related to incorrect login credentials or settings.
- Password changes must be updated on every device using the email account.
- Using only the mailbox name instead of the full email address can cause authentication failure.
- SSL/TLS encryption is required for secure SMTP authentication on Domains.co.za servers.
- Some email apps block authentication if encryption is disabled.
- Repeated failed login attempts can trigger temporary account restrictions.
- Third-party apps must support authenticated SMTP to send mail successfully.
Login to Domains.co.za Account
1. Go to the Domains.co.za website Account Login page.
2. Enter your Email and Password and click the Sign In button.
3. You will see the Domains.co.za Dashboard, displaying the Manage Account menu on the left and your Account Information, Account Overview and Open Support Tickets on the right.
