Summary
Even with opt-ins and showing as delivered, Marketo emails may not reach Gmail inboxes due to a confluence of factors impacting sender reputation, email content, and recipient-side configurations. Core issues include: the difference between deliverability (reaching the server) and inbox placement (landing in the inbox), Gmail's filtering based on sender reputation, content, and user engagement (even with opt-ins), potential misdirection by recipient-side filters/rules or Gmail's tabbed inbox, and the crucial role of email authentication (SPF, DKIM, DMARC). List hygiene, IP warm-up for new IP addresses, feedback loops for spam complaints, and avoiding spam trigger words are also highlighted. A double-opt-in process to prevent list bombing and ensure deliverability to validated addresses is essential. Analysis of server logs may also be required to confirm successful handoff to Gmail's servers and address any segmentation or non-sendable status issues.
Key findings
- Delivery vs. Inbox Placement: "Delivered" status only confirms email acceptance by Gmail's server, not inbox arrival.
- Gmail Filtering Criteria: Gmail filters based on sender reputation, content, user engagement, and recipient-specific settings, even with explicit opt-ins.
- Importance of Authentication: SPF, DKIM, and DMARC are critical for proving sender legitimacy and improving deliverability.
- List Hygiene & Opt-in: Proper list management, including double opt-in, is critical for address validation and sender reputation.
- Impact of Content & Format: Email content and format impact deliverability; avoiding spam trigger words and excessive imagery is key.
Key considerations
- Implement Double Opt-In: Employ double opt-in to ensure valid and consenting email addresses.
- Authenticate Your Emails: Configure SPF, DKIM, and DMARC to verify sender identity.
- Maintain List Hygiene: Regularly clean your email list, removing inactive subscribers.
- Optimize Email Content: Avoid spam trigger words, excessive imagery, and promotional language.
- Warm Up New IP Addresses: Gradually increase sending volume from new IP addresses to build sender reputation.
- Monitor Engagement & Feedback: Monitor open rates, click-through rates, and spam complaints to assess deliverability.
- Investigate Delivery Issues: Check recipient settings and analyze server logs to troubleshoot email delivery problems.
What email marketers say
12 marketer opinions
Even with opt-ins and emails showing as delivered, Marketo emails might not reach Gmail inboxes due to various factors. These include: recipient-side issues like filters or rules, use of third-party email clients, or emails landing in different tabs (Promotions, Updates). Sender reputation is crucial, influenced by email authentication (SPF, DKIM, DMARC), engagement rates, spam complaints, and list hygiene. Content and format can also play a role, with excessive use of images, links, and promotional language potentially triggering spam filters. IP warm-up for new IP addresses, audience segmentation, avoiding spam trigger words, and dedicated IP addresses are additional factors to consider.
Key opinions
- Recipient Factors: Recipient settings such as filters, rules, and use of third-party email clients can misdirect emails.
- Tabbed Inbox: Emails might be delivered but filtered into Gmail's Promotions or Updates tabs.
- Sender Reputation: Gmail's filtering heavily relies on sender reputation, which is influenced by authentication, engagement, and spam complaints.
- Content Matters: Email content and format can trigger spam filters, affecting inbox placement.
- List Hygiene: Poor list hygiene negatively impacts sender reputation and deliverability.
Key considerations
- Check Recipient Settings: Ensure recipients haven't set up filters or rules that misdirect emails.
- Email Authentication: Implement and maintain proper email authentication (SPF, DKIM, DMARC).
- Improve Engagement: Increase email engagement by personalizing content, segmenting your audience, and optimizing subject lines.
- Clean Email Lists: Regularly clean email lists by removing inactive subscribers and unsubscribes.
- IP Warm-up: If using a new IP address, gradually warm it up to establish a positive sender reputation.
- Avoid Spam Triggers: Avoid using spam trigger words and excessive promotional language in email content.
- Monitor Delivery Logs: Monitor email delivery logs to verify successful delivery to recipient mail servers.
Marketer view
Marketer from Email Geeks suggests checking the delivery log files for the specific message ID to verify if the email was truly delivered to the recipient's mail server. The SMTP response should have a 250 OK to confirm delivery. Shad Taylor recommends filtering the logs by destination email address to narrow down the issue. Shad also is curious if Marketo allows you to see these types of logs or do you have to contact support to see them.
10 Dec 2021 - Email Geeks
Marketer view
Email marketer from Mailchimp shares segmenting your audience based on demographics, behavior, or interests, you can send more relevant and targeted emails that are more likely to be opened and clicked. This can help improve your sender reputation and inbox placement in Gmail.
20 Apr 2024 - Mailchimp
What the experts say
4 expert opinions
Even with opt-ins and showing as delivered, Marketo emails might not reach Gmail inboxes. Troubleshooting steps include checking other Gmail tabs and sending test emails. While rare, Google doesn't always deliver every email to the inbox, even if accepted by its servers. Lack of double opt-in can lead to list bombing and unverified email addresses that may not receive emails. Factors such as sender reputation, email content, and user engagement influence Gmail's filtering decisions, potentially leading to emails being marked as unwanted and not delivered to the inbox. Contacting support to review server logs may clarify whether Gmail actually received the email or if it was blocked due to segmentation issues or non-sendable status.
Key opinions
- Delivery vs. Inbox Placement: 'Delivered' status doesn't guarantee inbox placement; Gmail may filter based on various factors.
- Gmail Filtering: Gmail filters emails based on sender reputation, content, and user engagement, even with opt-ins.
- Importance of Double Opt-in: Lack of double opt-in can lead to list bombing and delivery issues to unverified addresses.
- Log File Analysis: Server logs can clarify if Gmail received the email or if it was blocked for other reasons.
Key considerations
- Check Gmail Tabs: Advise users to check all Gmail tabs (e.g., Promotions, Updates) for missing emails.
- Implement Double Opt-in: Use double opt-in to ensure email addresses are valid and users genuinely want to receive emails.
- Review Sender Reputation: Monitor and improve sender reputation through authentication, engagement, and list hygiene.
- Analyze Server Logs: Contact support to review server logs and verify handoff to Gmail's mail servers.
Expert view
Expert from Email Geeks suggests contacting support to work with the MTA admin team to find the log file excerpt that proves handoff to Gmail's mail servers. If it did hand off then the issue is likely in a different folder or the users perception is incorrect, otherwise it likely did not send due to incorrect segmentation or a non-sendable status.
12 May 2023 - Email Geeks
Expert view
Expert from Word to the Wise, Laura Atkins, explains the issue of list bombing and the need for double opt-in. If accounts are being signed up without people knowing, then they are never verifying the address. Without verifying the address it's highly probable these accounts won't be able to get any email.
18 Feb 2025 - Word to the Wise
What the documentation says
5 technical articles
Marketo emails may not be reaching Gmail inboxes despite opt-ins and 'delivered' status due to factors such as sender reputation and email content. Google Support emphasizes the importance of authenticating emails using SPF, DKIM, and DMARC, sending wanted mail, and making it easy to unsubscribe. Mailjet distinguishes between deliverability (reaching the server) and inbox placement (landing in the inbox vs. spam folder), indicating that even delivered emails can end up in spam. SparkPost highlights sender reputation as a critical determinant of inbox placement. ReturnPath recommends setting up feedback loops to address spam complaints. Microsoft stresses that SPF, DKIM, and DMARC are essential for verifying sender identity and preventing spoofing, which Gmail uses to assess email legitimacy.
Key findings
- Authentication is Key: SPF, DKIM, and DMARC are essential for verifying sender identity.
- Deliverability vs. Inbox Placement: Reaching the server (deliverability) doesn't guarantee inbox placement.
- Sender Reputation Matters: Gmail uses sender reputation to decide whether to deliver to the inbox or spam.
- Feedback Loops Help: Feedback loops help identify and address spam complaints.
Key considerations
- Implement SPF, DKIM, DMARC: Ensure proper email authentication to improve sender reputation.
- Monitor Sender Reputation: Monitor and maintain a good sender reputation to ensure inbox placement.
- Obtain Explicit Consent: Only send emails to recipients who have opted in.
- Easy Unsubscribe Process: Provide a clear and easy way for recipients to unsubscribe.
- Set Up Feedback Loops: Implement feedback loops to handle spam complaints effectively.
Technical article
Documentation from Google Support explains that senders should authenticate their email using SPF, DKIM, and DMARC. They should also ensure they are sending wanted mail and making it easy to unsubscribe.
25 Dec 2023 - Google Support
Technical article
Documentation from Microsoft explains that implementing email authentication methods like SPF, DKIM, and DMARC is crucial for verifying the sender's identity and preventing email spoofing. Gmail uses these authentication records to determine the legitimacy of incoming emails.
16 Jan 2025 - Microsoft
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