Fix "550 Please turn on SMTP Authentication"
The server rejected your message because it was not authenticated. How to turn on SMTP authentication in common mail apps, and what to check if it is already on.
550 Please turn on SMTP Authentication means the server would not accept your
outgoing message because the connection did not prove who you are. Applies to
all WebGee mailboxes.
Outgoing mail always requires authentication. A server that relayed unauthenticated mail would be an open relay and would be blacklisted within hours.
Turn on SMTP authentication
The setting exists in every mail app, usually near the outgoing server configuration. It should be on, and set to use the same credentials as incoming mail.
Apple Mail (macOS)
- Mail → Settings → Accounts.
- Select the account, then the Server Settings tab.
- Under Outgoing Mail Server (SMTP), set Authentication to Password.
- Enter your full email address as the user name, and your mailbox password.
Microsoft Outlook
- File → Account Settings → Account Settings.
- Select the account, then Change → More Settings.
- On the Outgoing Server tab, tick My outgoing server (SMTP) requires authentication.
- Leave Use same settings as my incoming mail server selected.
Mozilla Thunderbird
- Account Settings → Outgoing Server (SMTP).
- Select the server, then Edit.
- Set Authentication method to Normal password.
- Enter your full email address as the user name.
iPhone and Android
Open the account's outgoing server settings and confirm the user name and password fields are filled in. Many devices leave them blank because the outgoing server is described as optional — it is not.
The user name is your full email address, including the domain. Entering
only the part before the @ is the single most common cause of this error.
If authentication is already on
Then the message is not reaching the server you think it is.
Check the outgoing server name. After a migration, apps often still point at a previous host. Compare it against Email server settings.
Check the MX records. If a domain transfer left the MX records pointing at the old provider, mail is being offered to a server that no longer accepts it.
Check your email routing. If the domain's mail is handled externally but cPanel still thinks it is local — or the reverse — sending fails. See Configure email routing in cPanel.
Check SPF. If you send through an external provider such as Google Workspace, your SPF record must authorise it, or receiving servers will reject the mail as unauthenticated. See SPF records for WebGee hosting.
Verify
Send a test message to an address outside your domain and confirm it arrives.
If it still fails, capture the full rejection text — the wording after the 550
identifies which check failed, and a different message points somewhere else
entirely. See
Read email headers.
Related
Fix "550 Sender verify failed"
This rejection means the address you are sending from does not exist on the server, or the domain's email routing is set the wrong way. How to check both.
Fix "550 This message was classified as SPAM"
Your outgoing message was scored as spam and returned. What raises the score, and the SMTP authentication setting that is usually responsible.