Summary
If you can receive emails but cannot send, it’s usually SMTP settings, authentication, or DNS policy.
Step 1: Confirm SMTP Settings
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Use settings from cPanel → Email Accounts → Connect Devices
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Check SMTP port: 587 (STARTTLS) or 465 (SSL)
Step 2: Ensure “SMTP Authentication” is ON
In Outlook/Phone mail app:
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Outgoing server requires sign-in: Enabled
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Username: full email address
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Password: email password
Step 3: Check SPF/DKIM/DMARC
Incorrect DNS policy can cause rejections or spam.
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Use the deliverability article (#6)
Common Error Meanings
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“550”: rejected by receiving server (policy, spam, auth, or DNS)
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“Authentication failed”: wrong password or wrong username format
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Timeout: network/port blocked or wrong server/port
What to send support (fast resolution)
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Screenshot of error
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Email address used
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App type (Outlook/Android/iPhone)
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Time the error happened
