SMTP Error 553 indicates that the recipient email address is formatted incorrectly or does not meet the receiving server’s address syntax requirements. This error occurs before delivery is attempted because the server cannot interpret the address as valid.
This is a permanent failure, meaning the message will not be resent automatically. Correcting the address format is necessary before successful delivery will occur.
TABLE OF CONTENTS
How to Resolve SMTP Error 553
1. Ensure the email address includes an @ symbol and a valid domain name.
2. Remove any spaces, commas, or unsupported special characters.
3. Confirm that the domain name is spelled correctly and exists.
4. Avoid including display names, brackets, or quotation marks in the address field.
5. Validate email addresses when using forms or automated systems.
6. Correct the address and resend the message.
Additional Information
- SMTP Error 553 is often caused by simple typing mistakes or copy-and-paste errors.
- Some mail servers apply stricter validation rules than others.
- Automated email systems should always validate address formatting before sending.
- Sending to invalid address formats increases bounce rates and affects deliverability.
- This error is always treated as a permanent failure by mail servers.
- Proper address validation improves overall email reliability.
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.
