Does this match what you’re seeing?
- 535 Incorrect authentication data
- SMTP authentication failed or ‘username and password not accepted’
- 550 relay not permitted
1. Username is the full address
you@yourdomain.co.uk, not you.
2. Password is the mailbox password
Not your DirectAdmin or client area password. If unsure, reset it in E-mail Manager then E-mail Accounts and enter the new one. How to change an email account password
3. Authentication is switched on
“Relay not permitted” or “relaying denied” means the app didn’t log in at all. Enable outgoing authentication, using the same credentials as incoming.
4. Method
Choose Normal password or Password. Avoid “Encrypted password”, “NTLM” or “OAuth2” for Traxio mailboxes.
5. Too many failed attempts
A device retrying an old password can trigger a temporary block for that connection, so even correct details fail for a while. Update or remove the old password on every device — phones, tablets, printers, websites — then wait before retrying.
6. Websites and plugins
- Check for trailing spaces in the saved password
- Special characters in PHP config files may need escaping
- The plugin’s encryption setting must match the port (SSL with 465, TLS with 587)
How to send WordPress email through SMTP
7. The domain in the server name
mail.yourdomain.co.uk must resolve to your Traxio server. If your DNS is elsewhere, check the mail record exists there. SPF, DKIM and DMARC when your DNS isn’t at Traxio