If your email client shows “Authentication failed”, it means the mail server rejected the login attempt when the email program tried to sign in to your account.

This usually happens when the username, password, or authentication settings are incorrect, or when the email client cannot properly verify your account.

Common causes include:

1. Incorrect password
   The password entered in the email client may be wrong or may have recently been changed. To change update your password please follow the steps in these articles: 

   • How to change your Cloud email password

   • How to change your Plesk email password 

   • How to change our Classic email password 

      

2. Incorrect username
   Many email services require the full email address (for example, name@domain.com) as the username instead of just the mailbox name. Please be sure you are using the correct email address as the username with the corresponding password. 

    

3. Password was recently updated
   If you changed your email password in webmail or your hosting panel, the email client will still be using the old password until it is updated.

    

4. Incorrect mail server settings
   If the incoming (IMAP/POP) or outgoing (SMTP) server settings are wrong, the server may reject the login request. 

   • Please follow our email set-up assistant if you need to find your correct email settings.

      

5. Authentication disabled for outgoing mail
   Some email clients require SMTP authentication to be enabled. If this setting is turned off, sending email may fail.

If you are still having some issues you are able to read further on email troubleshooting in this article: Email not working? How to troubleshoot your email.

If you are experiencing issues or have any questions, please feel free to contact our support team at service@rebel.com anytime, or you are able to speak to a live agent through chat or call 1-866-642-1232