Why am I seeing bounce issues when my HTML is UTF-8 with copyright characters?

Key findings

• Targeted Bounces: Bounce spikes are often observed on specific email domains, indicating varying levels of strictness in how different ISPs handle email character encoding.
• Invalid 7bit DATA: Bounce messages commonly cite 'invalid 7bit DATA', even when the HTML is declared as UTF-8, pointing to an issue with how the email content is actually being transmitted.
• Non-ASCII Characters: Characters outside the standard 7-bit ASCII range (e.g., em dashes, copyright symbols) are a primary culprit when sent with an inappropriate Content-Transfer-Encoding.
• ESP Role: The email service provider (ESP) plays a crucial role in correctly handling character encoding and MIME message creation, with their configuration often being the source of the problem.

Key considerations

• Review ESP Settings: Confirm that your ESP is configured to use an appropriate Content-Transfer-Encoding (like quoted-printable or base64) when sending HTML emails with UTF-8 characters, even common ones.
• Examine DSNs: Carefully analyze Delivery Status Notification (DSN) messages for precise error codes and descriptions that can pinpoint the encoding issue.
• HTML Entities: As a short-term workaround, consider converting special characters to HTML entities (e.g., © for ©) to avoid direct character encoding problems.
• Page Encoding: Ensure that your web pages or email templates consistently declare and use the correct character encoding, as highlighted by SEO best practices for character encoding.

Key opinions

• Platform Limitations: Many marketers express frustration when their ESP (email service provider) suggests avoiding common special characters, highlighting a perceived failing in basic platform functionality.
• Unexpected Bounces: The issue of bounces due to seemingly benign characters like the copyright symbol comes as a surprise, especially to experienced email coders who expect modern platforms to handle UTF-8 correctly.
• ESP Responsibility: There's a strong sentiment that the ESP should be responsible for correctly encoding messages, not forcing marketers to strip content that is part of standard design.
• Debugging Difficulty: Troubleshooting character encoding issues can be complex, often requiring analysis of DSNs or direct communication with ESP support, which can be time-consuming.

Key considerations

• ESP Configuration: Marketers need to verify how their ESP handles Content-Transfer-Encoding and whether it supports UTF-8 without causing malformed HTML or bounce issues.
• Alternative Encoding: While not ideal, some marketers may consider using HTML entities or modifying content to bypass immediate encoding problems with their current ESP.
• Switching Providers: If an ESP's limitations are severe and impact fundamental email deliverability, it may be a strong indicator to seek a more capable provider.
• Character Set Declaration: Marketers should always explicitly declare character encoding (e.g., <meta charset="UTF-8">) within their HTML and ensure it aligns with the sending method.

Key opinions

• Encoding Mismatch: The core issue is often sending high-ASCII or Unicode characters (which are 8-bit or multi-byte) with a Content-Transfer-Encoding of 7bit.
• Correct CTE: For UTF-8 content, the appropriate CTE should be quoted-printable or 8bitmime.
• ESP Accountability: Experts find it unacceptable for an ESP to advise clients to remove standard characters, as handling encoding is a fundamental responsibility of an email sending platform.
• Protocol Level Fixes: The solution lies at the protocol level, configuring the sending system (or ESP) to correctly declare and encode the email's content for transmission.

Key considerations

• ESPs and Encoding: Clients should ensure their ESP automatically handles character encoding correctly for various content types, reflecting compliance with MIME standards.
• Escalation Path: If first-tier support from an ESP provides inadequate solutions, users should escalate the issue, as character encoding is a critical deliverability factor.
• MIME Message Creation: Understand whether you or your ESP are responsible for creating the MIME message headers, particularly the Content-Transfer-Encoding one, to diagnose where the issue lies.
• Platform Choice: A reliable ESP should manage character encoding seamlessly, allowing marketers to focus on content creation rather than technical transmission details, as noted by deliverability resources.

Key findings

• MIME Standards: RFCs like RFC 2045 (MIME Part One: Format of Internet Message Bodies) dictate how email content should be structured and encoded, including the use of Content-Transfer-Encoding.
• 7bit Limitation: The 7bit Content-Transfer-Encoding is explicitly designed for messages that consist solely of 7-bit ASCII characters and should not be used for UTF-8 content containing non-ASCII characters.
• Recommended Encoding: For UTF-8 content, quoted-printable or base64 are the specified encodings to ensure all characters are transmitted correctly.
• Recipient Server Enforcement: ISPs (like plus.com and talktalk) and other mail servers may reject emails that violate these encoding rules, resulting in bounce messages and non-delivery.

Key considerations

• Character Set Declaration: Always declare the character set (e.g., charset=UTF-8) in the email headers and the HTML <meta> tag to inform mail clients of the encoding.
• Content-Transfer-Encoding Header: Ensure the Content-Transfer-Encoding header (part of the MIME message) is correctly set by your sending system or ESP to accommodate the characters used.
• RFC Compliance: Adherence to MIME RFCs is crucial for ensuring email deliverability across various mail servers and clients.
• Impact on Deliverability: Encoding issues can lead to increased bounce rates and potentially negative sender reputation, affecting overall email deliverability.