SMTP Error 450 occurs when the recipient’s mailbox is temporarily unable to receive email messages. This can happen if the mailbox is locked, undergoing maintenance, or experiencing a temporary server-side issue.
This error does not indicate a permanent delivery failure and usually resolves once the mailbox is available again. This guide explains how to handle SMTP Error 450 when sending email from a Domains.co.za email account.
TABLE OF CONTENTS
How to Resolve SMTP Error 450
1. Review the bounce-back message and confirm SMTP Error 450 is listed.
2. Verify that the recipient email address is correct and active.
3. Wait 30 to 60 minutes before attempting to resend the email.
4. Ask the recipient to confirm their mailbox is functioning correctly.
5. Remove large attachments and resend the message if necessary.
6. Login to your Domains.co.za account.
7. From your dashboard, open the Manage Services menu and select the hosting service linked to the domain you wish to manage.
8. Click Manage next to the relevant domain, then select Login to cPanel.
9. Open Track Delivery to review the delivery attempt.
10. Confirm that the message status displays as deferred.
11. Retry sending the email after the waiting period.
Additional Information
- SMTP Error 450 indicates a temporary mailbox condition rather than a permanent rejection.
- The recipient’s mailbox may be locked during maintenance, updates, or system checks.
- Storage-related issues on the recipient side can temporarily prevent delivery.
- Large or complex messages may take longer to process and trigger deferrals.
- This error does not negatively affect your domain’s sending reputation.
- Messages are often delivered automatically without user intervention.
- Persistent errors may require the recipient to contact their mail provider.
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.
