Summary
When Mailchimp emails show as 'delivered' but don't reach the inbox, spam folder, or anywhere, the problem often lies beyond Mailchimp's sending process. A 'delivered' status merely confirms the receiving server's acceptance, not inbox placement. Several factors influence final delivery: the recipient server's spam filters, sender reputation, email authentication (SPF, DKIM, DMARC), list hygiene, email content (size, rendering), and recipient-side security (firewalls, greylisting). Some servers silently drop emails, and corporate domains often have stricter filtering. Monitoring tools like Google Postmaster Tools and Microsoft SNDS help track reputation, while understanding bounce types aids in troubleshooting. Maintaining clean lists, optimizing content, and staying updated with authentication protocols are crucial for improving deliverability.
Key findings
- 'Delivered' Doesn't Equal 'Inbox': A 'delivered' status only means the receiving server accepted the email, not that it reached the recipient's inbox.
- The Receiving End Matters: The issue is often on the receiving end, involving factors like spam filters and domain policies.
- Silent Drops Exist: Some email providers or domains silently delete or drop emails, often as a spam-fighting technique.
- Reputation is Key: A good sender reputation is crucial for avoiding spam filters and improving deliverability.
- Authentication is Essential: Proper authentication (SPF, DKIM, DMARC) is essential for proving sender legitimacy and preventing email spoofing.
- List Hygiene Matters: Maintaining a clean and engaged email list is vital for avoiding spam traps and improving deliverability.
- Email Size Affects Deliverability: Large email sizes can negatively impact inbox placement; compressing images and optimizing size helps.
- Greylisting Causes Delays: Greylisting can temporarily reject emails, leading to delays if the sender's server doesn't retry.
- Corporate Domains Are Different: Corporate email systems often have stricter filtering, and whitelisting may be necessary.
- Monitoring Tools are Important: Tools like Google Postmaster Tools and Microsoft SNDS help monitor domain and IP reputation.
Key considerations
- Monitor Sender Reputation: Regularly check sender reputation scores using tools and services.
- Implement Proper Authentication: Ensure SPF, DKIM, and DMARC are correctly configured and up-to-date.
- Practice Strict List Hygiene: Remove inactive subscribers, suppress unsubscribes, and regularly clean the email list.
- Optimize Email Content: Reduce email size, avoid spam trigger words, and ensure proper rendering across different email clients.
- Investigate Delivery Issues: When emails are not being delivered, investigate with the recipient's IT support or email provider, especially for corporate domains.
- Be Aware of Silent Drops: Recognize that some email servers may silently drop emails, making troubleshooting difficult.
- Consider Greylisting: Account for the potential impact of greylisting on email delivery delays.
- Understand Bounce Types: Analyze bounce codes to understand why emails are not being delivered and address underlying issues.
What email marketers say
12 marketer opinions
Emails showing as 'delivered' in Mailchimp doesn't guarantee inbox placement. The issue often lies on the receiving end, influenced by factors like sender reputation, authentication (SPF, DKIM, DMARC), list hygiene, content, and recipient-side security measures. Corporate firewalls, greylisting, and email rendering issues can also prevent emails from reaching the intended recipient. Monitoring bounce rates, spam complaints, and sender reputation is essential, along with implementing best practices for list management and authentication.
Key opinions
- Acceptance != Inbox: A 'delivered' status only means the receiving server accepted the email, not that it reached the inbox.
- Size Matters: Large email sizes (over 1MB) can negatively impact inbox placement. Compressing images and optimizing email size can improve deliverability.
- Corporate Domains: Corporate email systems often have stricter filtering, and whitelisting may be necessary.
- Bounce Types: Understanding hard vs. soft bounces helps diagnose deliverability issues.
- Reputation Counts: A good sender reputation is crucial for avoiding spam filters.
- Authentication is Key: Proper authentication (SPF, DKIM, DMARC) is essential for proving sender legitimacy.
- List Hygiene Matters: Maintaining a clean email list with engaged subscribers improves deliverability.
- Gmail Blocking: Gmail can block emails even after showing as delivered, requiring diligent monitoring and DMARC implementation.
- Rendering can lead to spam: Email rendering issues can make email look bad and lead to recipients deleting or marking as spam.
- Whitelisting can help: In corporate environments, whitelisting the sender’s domain or IP address on the recipient’s end might be necessary.
Key considerations
- Monitor Sender Reputation: Regularly check sender reputation scores using tools like Google Postmaster Tools and Microsoft SNDS.
- Implement Authentication: Ensure SPF, DKIM, and DMARC are correctly configured to authenticate emails.
- Practice List Hygiene: Remove inactive subscribers, suppress unsubscribes, and regularly clean the email list.
- Optimize Email Content: Reduce email size, avoid spam trigger words, and ensure proper rendering across devices.
- Monitor Bounce Rates: Analyze bounce rates and address any issues promptly.
- Manage Complaints: Keep complaint rates low by sending relevant and engaging content.
- Be Aware of Silent Drops: Be aware that corporate firewalls can silently drop emails even if they pass initial server checks. Work with the recipient's IT department or email provider to determine why the emails are not being delivered.
- Consider Greylisting: Greylisting can cause emails to be delayed or seem lost if the server does not retry.
Marketer view
Email marketer from Litmus shares that email rendering issues can affect whether emails are properly displayed, potentially leading recipients to delete or mark emails as spam. Ensuring emails are responsive and tested across different email clients and devices is crucial for improving engagement and deliverability.
14 May 2024 - Litmus
Marketer view
Marketer from Email Geeks responds that they've seen this happening quite a lot with our users on corporate domains that has microsoft and that when they whitelist our email address the email appears.
15 Feb 2023 - Email Geeks
What the experts say
6 expert opinions
Emails seemingly disappearing after showing as 'delivered' can stem from various technical configurations and policies. Silent deletes or drops, often used as spam-fighting techniques, can cause emails to vanish without a trace. The domain's email handling policies play a crucial role, with some domains, particularly corporate or hobbyist ones, employing silent drops. Shared IP pools can delay delivery, making emails appear missing. Greylisting, a spam defense tactic, temporarily rejects emails, and issues with authentication policies (SPF, DKIM, DMARC) can lead to emails being filtered or blocked. The absence of bounce messages suggests emails are being dropped before a bounce notification can be generated, highlighting the need to investigate with the recipient's IT department.
Key opinions
- Silent Deletes/Drops: Email providers or domains can silently delete or drop emails as a spam-fighting technique or due to specific configurations.
- Domain Policies Matter: The handling of emails depends on the domain's specific policies, with some domains more prone to silent drops.
- Shared IP Pool Delays: Big sends from shared IP pools can experience delays, causing emails to appear missing initially.
- Greylisting Effect: Greylisting can temporarily reject emails, leading to delays if the sender's server doesn't retry.
- Authentication Issues: Incorrect or outdated SPF, DKIM, or DMARC configurations can cause emails to be blocked or sent to spam.
- Lack of Bounce Messages: The absence of bounce messages may indicate that emails are silently dropped before a bounce can be generated.
Key considerations
- Investigate Domain Policies: Inquire with the recipient's domain owner or IT department about their email handling policies, particularly regarding silent drops.
- Monitor IP Reputation: If using shared IP pools, monitor IP reputation to identify potential deliverability issues.
- Verify Authentication: Regularly check and update SPF, DKIM, and DMARC records to ensure proper email authentication.
- Check for Greylisting: Be aware of greylisting and ensure your email server retries after temporary rejections.
- Contact IT Support: If emails are not generating bounce messages and are not being delivered, contact the recipient's IT support to investigate further.
- Understand Consumer vs. Corporate Delivery: Delivery behavior and success can differ between consumer-based email addresses vs. corporate email domains.
Expert view
Expert from Word to the Wise answers shares that a potential reason for email delivery problems could be due to changes in authentication policies. She goes on to state that it is important to keep up-to-date with SPF, DKIM, and DMARC configurations, as these are essential to preventing email from going to spam or being blocked.
2 Jun 2022 - Word to the Wise
Expert view
Expert from Spam Resource explains that greylisting is used by some email servers as a spam defense. If a server greylists, they temporarily reject the first attempt to deliver an email from an unknown sender. Legitimate servers will retry, but spammers often don't. This could be a reason for delayed or seemingly lost emails.
22 Mar 2022 - Spam Resource
What the documentation says
3 technical articles
A '250 OK' SMTP response only indicates that the receiving server accepted the email, not that it successfully reached the recipient's inbox. Spam filtering and other factors can still prevent delivery after acceptance. Monitoring domain and IP reputation using tools like Google Postmaster Tools and Microsoft SNDS is crucial for identifying issues such as spam complaints, authentication problems, and spam traps, all of which can lead to emails being filtered or blocked.
Key findings
- '250 OK' Isn't a Guarantee: An SMTP '250 OK' response confirms acceptance by the server but not inbox delivery.
- Reputation Matters: Low domain or IP reputation can lead to emails being filtered or blocked.
- Google Postmaster Tools: Google Postmaster Tools helps monitor domain reputation with Google.
- Microsoft SNDS: Microsoft SNDS helps monitor IP reputation with Microsoft and identify issues affecting delivery to Outlook.com and Hotmail.
Key considerations
- Monitor Reputation: Regularly monitor domain and IP reputation using tools like Google Postmaster Tools and Microsoft SNDS.
- Address Issues: Promptly address issues identified by reputation monitoring tools, such as spam complaints, authentication problems, and spam traps.
- Understand SMTP Responses: Recognize that a '250 OK' response doesn't guarantee inbox delivery, and investigate further if emails are not reaching recipients.
Technical article
Documentation from RFC explains that SMTP servers use response codes to indicate the status of email delivery. A '250 OK' response means the message was accepted, but it doesn't guarantee it reached the inbox. Issues such as spam filtering can still prevent delivery even after acceptance.
12 Feb 2024 - RFC
Technical article
Documentation from Google Postmaster Tools explains how to monitor your domain's reputation with Google. Low reputation scores may indicate issues with spam complaints, authentication, or sending practices, which can result in emails being filtered or blocked.
21 Feb 2024 - Google
