Deliverability
It’s frustrating as an email sender when your messages don’t get through. Especially if you don’t know why it’s happening. In this article, we’ll dig into why Gmail may be blocking your emails, cover some of the new Gmail inbox protocols, and leave you with some suggestions on how to improve your email deliverability. The inbox world is selective. Trust us, you’ll want these tips.
So, you’re frustrated with blocked emails on Gmail. After all, you’re not a spammer, so why is this happening to you? Not only are there many possible culprits, but some of the reasons have bigger consequences than they used to due to Gmail inbox updates and new sender requirements being implemented in early 2024. If your emails are being blocked and your spam complaint rate gets too high as a result, you could find that all of your messages start making their way directly to the spam folder.
With the new sender requirements implemented by Gmail and Yahoo, stricter authentication protocols like DMARC are now being enforced to verify the legitimacy of bulk senders. Other requirements such as a cap on acceptable spam complaint rates, and enforcement of a one-click unsubscribe link may result in more legitimate senders being viewed as spammers.
Here are the most common reasons why Gmail might be blocking your emails:
Let’s look at each of these in detail.
Gmail imposes a limit of 25Mb per image and 100 images per email. If you include multiple images, try to reduce the number to keep your email under the limit. Besides, emails with a high number of images might get flagged as spam. If you’re not a spammer, avoid sending out spammy-looking content! Otherwise, you might land in Gmail’s spam folder.
Gmail doesn’t allow certain types of attachments, like .exe files and .zip files. This is because these attachment types can be associated with malware. If you’re trying to include an attachment that’s not allowed, you’ll need to find another way to send it.
If your email is missing a subject, Gmail will automatically block it. This is because emails without subject lines are often spam emails. Fix your subject lines to dodge the spam filter. Check out our tools to make sure your subject lines pass muster!
Gmail doesn’t allow certain types of HTML in emails, including:
If your email contains HTML that’s not allowed, try removing it and resending the email.
Gmail has a built-in scanner that will block emails that contain viruses or malware. If your email is being blocked because it contains either, you’ll need to remove it before sending the email.
If you’ve ended up on Gmail’s blocklist, your message might be blocked by Gmail. Learn more about blocklists, and how to delist your IP address if you’ve landed on a blocklist.
If you’ve been acting like a spammer by sending high volumes of content to inactive or invalid email addresses, your IP and sender reputations suffer. Moreover, if you’ve received a high volume of spam complaints from your subscribers, Gmail might decide not to deliver your emails.
Gmail’s advanced filtering systems analyze email content and sender behavior overall, flagging suspicious emails and blocking those that don’t comply with all of the requirements collectively. Consistency is the key. If you consistently send in compliance with Gmail standards, the occasional spike in complaint rate on a campaign will hurt you much less than if your practices constantly raise flags.
If too many of your emails bounce back, Gmail may refuse to deliver your emails. Keep your bounce rates low to keep your deliverability high.
Gmail is on high alert for phishing emails and spoofing, especially with stricter standards now enforced across Google Workspace and other platforms. If your emails are missing essential DNS records or have misaligned DKIM signatures, Gmail may flag your message as suspicious – even if you’re a legitimate sender.
Phishing filters often look for mismatched sender domains, sketchy links, and poor SMTP authentication. Make sure your email headers clearly align with your domain identity and that your Mailgun sending domain passes DMARC checks. This helps reassure Gmail that your message isn’t coming from a bad actor.
If Gmail sees signals it doesn’t trust, it may block your message outright – or push a warning to recipients, hurting engagement on your future emails.
If Gmail is blocking incoming emails from you, it’s not the end of the world. Here are some Gmail best practices to prevent blocked messages in Gmail:
Use email authentication: Ensure your DMARC, DKIM, and SPF records are properly set up – these are your “ID cards” for sending emails. Also, make sure to set up your Domain Name Service (DNS) record to display your sender’s name. This way, Gmail knows you are who you say you are and is less likely to flag you as a spammer. Gmail and Yahoo both require bulk senders to have implemented DMARC with a policy of p=none.
Provide a single-click process for subscribers to unsubscribe: If your subscribers aren’t given a way to opt out with a single click, Gmail will flag your messages as unwanted emails – and worse, Gmail users might just mark your email messages as spam. While this doesn’t mean much for your recipients (they get the same result: not seeing your emails land in their email account), too many spam complaints can land you on a blocklist. And any spam rate higher than 0.3% will land you in the spam folder according to the new Gmail inbox protocols.
Clean your email list: Maintain your email list hygiene by regularly verifying email addresses and removing invalid users. This way, you can reduce your email bounce rate and improve your deliverability.
Monitor Google Postmaster: Monitor your messages to Gmail with Google Postmaster Tools to track metrics around open rate, click-through rate, bounce rate, conversions, engagement, and authentication status. Especially with enhanced inbox protocols, monitoring for specific inboxes will be key in maintaining a strong sender reputation.
Keeping an eye on your sending behavior is key to staying within Gmail’s thresholds and maintaining a strong sender reputation. Lucky for you, Mailgun’s built-in integration with Google Postmaster lets you easily track your Gmail deliverability metrics right from your dashboard.
Preview emails before sending: It’s always a good idea to test how your emails render across different email services. Inconsistent formatting – especially between platforms like Gmail and Outlook – can impact deliverability and even land your emails in the spam folder.
There are many reasons Gmail can block your emails, and a few tried and true paths to unblock them. It’s also possible that the reason you’re messages are being blocked are not easily solved by our reasons in this post. Deliverability is nothing if not complex. But don’t worry – by following these best practices, you’ll increase the likelihood that future emails will land in the inbox, not the spam folder. Need more help? Take advantage of our deliverability services and the InboxReady Google Postmaster Tools to see how Gmail perceives your reputation and manages your incoming messages.
With Google Postmaster Tools now integrated into the Mailgun Optimize suite, you get access to your most essential testing and monitoring tools, all in one convenient place. What better way to improve your Gmail deliverability than using the tools Gmail provides?
