What does 'delivered' actually mean if my emails aren't in the inbox?

The delivered status means the receiving server (Gmail) accepted the email. It does not guarantee it landed in the primary inbox. Gmail may filter it to other tabs (Promotions, Social) or even the spam folder based on various factors like sender reputation, authentication, and content.

Why would my emails not arrive even if recipients opted in?

Even with opt-ins, factors like low engagement, high complaint rates, poor sender reputation (domain and IP), and issues with email authentication (SPF, DKIM, DMARC) can cause Gmail to filter your emails more strictly. Content that appears spammy can also play a role.

How can I investigate the problem beyond Marketo's basic 'delivered' status?

Request detailed SMTP logs from Marketo support. Look for the 250 OK response, which confirms Gmail's server accepted the email. Also, regularly monitor your sender reputation using Google Postmaster Tools .

What role does email authentication play in Gmail deliverability?

Ensure your SPF, DKIM, and DMARC records are correctly configured and aligned. Google and Yahoo now require strong authentication for bulk senders. If your email authentication is not in order, your messages are more likely to be filtered to spam.

What should recipients do if they can't find my Marketo emails?

Ask your recipients to check all Gmail tabs (Promotions, Social, Updates), their spam folder, and to use the search function for your emails. Sometimes, recipient-side filtering rules or third-party email clients can also affect visibility, as discussed in Google's support community .

Why are my Marketo emails not arriving in Gmail inboxes even with opt-ins and showing as delivered? - Troubleshooting - Email deliverability - Knowledge base

It can be incredibly frustrating when your emails, especially those sent through a reliable platform like Marketo, aren't reaching Gmail inboxes, even though your analytics show them as delivered. What makes it even more perplexing is when these are recipients who have explicitly opted in and have engaged with your emails in the past.

This situation points to a subtle, yet critical, distinction in email deliverability: delivered does not always mean in the inbox. An email platform reports an email as delivered once the receiving mail server, like Google's, accepts it. However, what happens next is entirely up to the recipient's email service provider and their filtering algorithms.

I'll delve into the common reasons why this occurs and provide actionable steps to help you troubleshoot and improve your Marketo email deliverability to Gmail.

Understanding 'delivered' versus inbox placement

When Marketo (or any email sending platform) reports an email as delivered, it means the email successfully completed the SMTP handshake with the recipient's mail server. The server returned a 250 OK response, indicating it accepted the email for local delivery. This doesn't guarantee the email lands in the primary inbox. It simply means it didn't bounce.

Many email marketers confuse delivery with inbox placement, but they are distinct concepts. Marketo itself defines delivered as not rejected by a receiving server, highlighting that delivered does not mean it landed in the recipients inbox. Gmail has sophisticated filtering systems that analyze various factors before deciding where to place an email: the primary inbox, promotions tab, spam folder, or sometimes, not displaying it at all in common views.

So, while your Marketo emails might have successfully reached Gmail's servers, they could be diverted to other tabs or folders without the recipient's immediate awareness. This is a common scenario, and it's why it's crucial to understand why an email might show as delivered but not received by the subscriber.

Common reasons for Marketo email non-arrival

Even with opt-ins and a Marketo Trusted IP, several factors can prevent your emails from reaching the primary Gmail inbox. These often relate to sender reputation and how Gmail's algorithms perceive your sending behavior.

Firstly, sender reputation is paramount. While being on a trusted IP is a good start, your domain's reputation also plays a huge role. Factors like spam complaint rates, bounce rates, open rates, and how often recipients move your emails out of spam or into their primary inbox all contribute to your sender score. A sudden dip in engagement or an increase in complaints can negatively impact this reputation, causing Gmail to filter your messages more aggressively.

Secondly, email authentication is critical. Ensure your SPF, DKIM, and DMARC records are correctly configured and aligned. Gmail and Yahoo (and others) have recently enforced stricter requirements for bulk senders, including strong authentication and aligned DMARC policies. A misconfiguration, even if subtle, can lead to messages being filtered. Learn about the difference between DMARC, SPF, and DKIM.

Lastly, email content and recipient engagement play a role. Even for opted-in lists, if your emails consistently trigger spam filters due to content (e.g., too many images, suspicious links, spammy keywords) or if recipients rarely open or frequently delete your emails without opening them, it can signal to Gmail that your messages are not desired, leading to filtering. You can find more information on why newsletters might go to spam.

Importance of authentication

Google and

Yahoo are increasingly focusing on sender authentication as a primary factor for inbox placement. Ensure your DMARC policy is actively monitoring and enforcing alignment for your sending domains.

You can use DMARC monitoring to gain visibility into your email authentication status and identify any issues that might be affecting deliverability.

Deep dive into troubleshooting steps

When facing these issues, the first step is always to gather more data beyond Marketo's delivered status. Here's how to start looking for clues:

Check recipient's Gmail account

Tabs and folders: Ask the recipients to check their Promotions, Social, and Updates tabs, as well as their spam folder. Sometimes, emails end up there without being explicitly marked as spam.
Search: Have them search their entire Gmail inbox, including all mail and archived messages, for your sender address or the email subject line. Gmail is designed to very rarely drop emails entirely.
Forwarding rules: It's possible the recipient has an individual forwarding rule set up that moves or deletes incoming messages before they appear in their main view, as discussed by users on Reddit.

Analyze Marketo and server-side logs

While Marketo's activity logs provide basic sent and delivered statuses, they often lack the granular detail needed for deep troubleshooting. You'll need access to the actual SMTP log files from Marketo's mail transfer agent (MTA). Contact Marketo support to request these logs for the specific message IDs in question. Look for the SMTP response code: a 250 OK confirms Gmail's server accepted the email.

Example SMTP 250 OK responsetext

250 2.1.5 Ok: queued as <messageID>

If the logs show a 250 OK, the issue is on Gmail's side, within the recipient's account, or related to your sender reputation causing internal filtering. If there's no 250 OK, it indicates a sending problem from Marketo's end, possibly due to suppression, segmentation issues, or an unexpected bounce that wasn't recorded properly. This is similar to what causes delivery problems to Gmail.

Advanced considerations and prevention

Beyond immediate troubleshooting, proactive measures are key to sustained Gmail inbox placement for your Marketo emails. These steps build a stronger sender reputation and ensure compliance with evolving email standards.

Monitor your sender reputation

Even with opt-ins, consistent monitoring of your sender reputation is vital. Utilize Google Postmaster Tools to track your domain's reputation, IP reputation, spam rate, and authentication errors. These insights are invaluable for understanding how Gmail perceives your sending practices. A sudden drop in reputation scores here can explain why emails are not reaching the inbox, even for engaged recipients.

Maintain list hygiene and engagement

Regularly clean your email list to remove inactive subscribers, hard bounces, and known spam traps. Even if contacts are opted-in, sending to unengaged addresses can negatively impact your overall sender reputation. Prioritize engagement by sending relevant, valuable content. High open rates and click-through rates signal to ISPs like Gmail that your emails are wanted and legitimate, improving your inbox placement.

Adhere to new email standards

Gmail and Yahoo have implemented new bulk sender requirements, effective February 2024. These require: strong email authentication (SPF, DKIM, DMARC), a clear one-click unsubscribe option, and keeping spam complaint rates extremely low. Non-compliance can lead to emails being rejected or sent straight to the spam folder, even with good opt-in practices. It's crucial to understand the new standards for bulk mail and adjust your Marketo sending practices accordingly. You can also monitor for what happens when your domain is on a blacklist.

Reactive approach

Waiting for sales reports or customer complaints about missing emails. Relying on basic

Marketo delivered metrics without deeper log analysis. Discovering issues only after they impact campaigns.

Proactive approach

Implementing blocklist monitoring and closely observing Gmail Postmaster Tools. Regularly reviewing detailed SMTP logs and DMARC reports. Adjusting sending behavior based on trends, not just incidents.

Views from the trenches

Best practices

Actively use Google Postmaster Tools for monitoring your domain and IP reputation.

Implement a strong DMARC policy (p=quarantine or p=reject) with proper alignment.

Regularly clean your email lists to maintain high engagement and reduce inactive addresses.

Send test emails to a variety of internal Gmail accounts, including newly created ones, to monitor placement.

Segment your audience effectively and send relevant content to minimize spam complaints.

Common pitfalls

Misinterpreting 'delivered' status as guaranteed inbox placement in Gmail.

Neglecting sender reputation metrics in favor of basic campaign reports.

Failing to implement or correctly configure DMARC, SPF, and DKIM authentication.

Ignoring low engagement from certain segments, which can harm overall sender reputation.

Not checking common Gmail tabs (Promotions, Social) or hidden folders for missing emails.

Expert tips

Set up Gmail Postmaster Tools for your sending domains. This provides invaluable data directly from Gmail.

Focus on engagement metrics: opens, clicks, and replies. Gmail values these signals.

If using a shared IP, understand that other senders on the IP can impact your deliverability.

Always include a clear, one-click unsubscribe link in all marketing emails.

Avoid sending to unengaged subscribers, even if they are opted-in, as it can harm your reputation.

Expert view

Expert from Email Geeks says that Google rarely drops emails entirely, so it is highly unlikely that emails are completely disappearing.

2023-11-18 - Email Geeks

Marketer view

Marketer from Email Geeks says that third-party email clients can sometimes affect how emails are received and displayed, making troubleshooting more complex.

2023-11-18 - Email Geeks

Improving your Marketo email deliverability to Gmail

Resolving Marketo email deliverability issues to Gmail, especially when emails show as delivered, requires a multi-faceted approach. It's rarely a single problem but rather a combination of factors related to sender reputation, authentication, content, and recipient engagement. Remember that email deliverability issues are complex.

By diligently checking recipient-side factors, analyzing detailed SMTP logs, proactively monitoring your sender reputation via Google Postmaster Tools, and adhering to the latest email standards, you can significantly improve your Marketo emails' chances of landing in the primary Gmail inbox. Persistent effort in these areas will yield better results than simply relying on delivered statistics alone.