Summary
The '553 5.1.3' bounce error from Gmail arises when the recipient's email address fails to comply with the RFC 5321 standard, which defines the valid format for email addresses. This can result from various issues, including incorrect storage, typos, invalid characters (including special characters and spaces), incorrect domain formatting, or system glitches that introduce non-compliant elements. Experts and documentation suggest a multi-pronged approach: validating email addresses at the point of entry, maintaining good list hygiene through regular cleaning, and scrutinizing email sending systems for unintended formatting.
Key findings
- RFC 5321 Non-Compliance: The recipient's email address does not conform to the RFC 5321 standard.
- Data Entry and Storage Issues: Errors can originate from typos, copy-paste mistakes, system glitches, or incorrect storage of email addresses.
- Format and Syntax Problems: Invalid characters (including spaces and special characters), incorrect syntax, or domain formatting can cause bounces.
- System-Introduced Errors: The email sending system might be automatically adding formatting or characters that violate RFC 5321.
Key considerations
- Email Validation at Entry: Implement real-time email validation on signup forms and other data entry points to prevent invalid addresses from entering your system.
- Regular List Hygiene: Maintain a clean email list by regularly removing invalid, inactive, or problematic email addresses.
- System Scrutiny: Thoroughly investigate your email sending system to identify and correct any automatic formatting or additions that might violate RFC 5321.
- Address Storage: Ensure email addresses are being stored correctly.
- Special Characters: Identify any special characters within the email that are not compliant to RFC 5321 and ensure they are corrected to remove errors.
What email marketers say
9 marketer opinions
The '553 5.1.3' bounce error from Gmail indicates that the recipient email address doesn't conform to the RFC 5321 standard, leading to the email being rejected. This can be caused by various issues, including typos, invalid characters, leading or trailing spaces, or a more fundamental syntax error in the email address. Addressing this problem involves proactive email validation, maintaining proper list hygiene, and troubleshooting potential issues within your email sending system.
Key opinions
- Invalid Format: The primary cause is an email address not conforming to RFC 5321, which dictates the valid syntax.
- Data Entry Errors: Typos, copy-paste errors, and system glitches can introduce invalid characters or spaces.
- System Issues: The email sending system itself might be adding invalid formatting.
Key considerations
- Email Validation: Implement real-time email validation on signup forms to prevent invalid addresses from entering your list.
- List Hygiene: Regularly clean your email list to remove invalid, inactive, or problematic email addresses.
- Troubleshooting: Check your email sending system for any automatic formatting or additions that might violate RFC 5321.
- Special Characters: Be aware of characters that are outside of the RFC 5321 specification and how your system handles them.
Marketer view
Email marketer from Reddit explains that this error usually points to a problem with your data, like a copy and paste error or a system glitch and suggests cleaning your email list to ensure all addresses are valid and correctly formatted.
26 Apr 2025 - Reddit
Marketer view
Email marketer from StackExchange recommends identifying any special characters within the email that are not compliant to RFC 5321 and ensure they are corrected to remove errors.
29 Nov 2022 - StackExchange
What the experts say
3 expert opinions
The '553 5.1.3' bounce error from Gmail indicates that the recipient email address doesn't conform to the RFC 5321 standard. Experts suggest this could be due to how addresses are stored, invalid formats including characters, spaces or incorrect domain formatting, and urge a focus on preemptive validation to catch these errors.
Key opinions
- Storage Issues: Email addresses might be stored incorrectly in the database, causing the error.
- Invalid Format: Invalid characters, spaces, or incorrect domain formatting are common causes of the error.
- Validation Needed: Preemptive email address validation is crucial to catch invalid formats before sending.
Key considerations
- Data Integrity: Check and correct how email addresses are stored to ensure they are RFC 5321 compliant.
- Format Verification: Implement checks for valid characters, spaces, and domain formatting in email addresses.
- Proactive Validation: Use email address validation techniques to catch errors before sending and improve deliverability.
Expert view
Expert from Spam Resource explains that the '553 5.1.3' error often stems from an invalid email address format, highlighting the importance of verifying the syntax of email addresses before sending. Common issues include invalid characters, spaces, or incorrect domain formatting.
19 Dec 2022 - Spam Resource
Expert view
Expert from Email Geeks suggests checking how the email addresses are stored, suspects the issue is with the email addresses stored incorrectly, and until recently either the ESP was cleaning them on send, or Gmail was accepting invalid addresses. He also provides a telnet example showing the error when a space is included in the recipient address.
20 Jan 2024 - Email Geeks
What the documentation says
4 technical articles
According to documentation from Google, Microsoft, IETF, and the RFC Editor, the '553 5.1.3' bounce error from Gmail signifies that the recipient's email address fails to comply with the RFC 5321 standard for valid email address formats. This non-compliance can manifest through invalid characters, incorrect syntax, or the presence of leading/trailing spaces. Adherence to RFC specifications is crucial for successful email delivery.
Key findings
- RFC 5321 Violation: The core issue is that the email address does not conform to the RFC 5321 standard.
- Syntax Errors: Specific errors include invalid characters, incorrect syntax, and leading/trailing spaces.
- Standards Compliance: Email addresses must adhere to Internet standards, particularly RFC specifications, for proper processing.
Key considerations
- Format Validation: Ensure that email addresses are validated to comply with RFC 5321 standards before sending.
- Character Restrictions: Pay attention to the allowed characters and syntax specified in RFC 5321 and related RFCs.
- Address Formatting: Avoid introducing invalid characters, incorrect syntax, or leading/trailing spaces in email addresses.
Technical article
Documentation from IETF refers to RFC 2822 (which was superseded by RFC 5322, but contains related information on email address format) which provides details on valid characters and syntax for email addresses. Proper formatting is crucial for email delivery.
9 Apr 2023 - IETF
Technical article
Documentation from Microsoft Support explains that email addresses must conform to Internet standards, including RFC specifications. Invalid characters or formatting can cause rejections by mail servers like Gmail.
12 Sep 2024 - Microsoft Support
Can Gmail give false positive SMTP bounce responses?
Can 'invalid recipient' bounce messages be false positives and what should I do about it?
How can I accurately verify my email list and identify potentially harmful domains?
How do I troubleshoot email bounce messages?
How do I validate the structure of an email account and what are some valid email address examples?
What causes '550 relaying denied' bounce errors and how to resolve them?
