How to determine the cause of a spam folder or email blocking issue

While most GMass users get the highest open and click-through rates they’ve ever seen with their email marketing campaigns, occasionally you might run into an issue where emails sent with GMass land in the Spam folder or are outright blocked, and the bounce message says you’ve been blocked.

Here is a step-by-step guide to determining the cause of the spam issue and how to solve it. This is the same set of steps our support team uses when helping a user through this issue, and with this guide, you should be able to self-diagnose the issue and fix it yourself.

Step 1: Send with Gmail’s “Send” button instead of the GMass button

Compose your email to the problematic email address, remove the unsubscribe link (if you included one) and send the exact same email with the Gmail Send button, instead of the GMass button.

Send with the regular Gmail “Send” button instead of the GMass button.
Did your email get delivered?

If so, now send it with the GMass button one more time to confirm that it’s GMass that’s causing the spam issue.

If you’ve determined that it’s GMass causing the issue, now move onto Step 2.

If your email still didn’t get delivered after using the Gmail Send button, then there’s something about the content of your email or source of your email (if you’re using an external SMTP service) that’s causing the issue, and the issue is unrelated to GMass.

Step 2: Turn tracking off, remove any unsubscribe links, and send again with GMass

When you send with the GMass button, GMass makes several changes to your email, depending on your Settings.

If you have Track Opens enabled, then GMass adds an open-tracking pixel to the bottom of your email.

If you have Track Clicks enabled, then GMass modifies your links to hit the GMass server first before redirecting to your final destination URL.

If you include the GMass unsubscribe link, then that link is personalized for each individual recipient.

Remove the changes that GMass makes to your email by turning OFF open tracking, turning OFF click tracking, and removing the unsubscribe link.

Turn off tracking and send with the GMass button.

Now, send your email with the GMass button again. Now an email receiver won’t be able to distinguish between sending with the Gmail Send button versus the GMass button.

Did your email get delivered?

If so, you know it’s an issue with GMass tracking. You should set up a dedicated tracking domain, which will almost certainly fix the issue, or if you like, you can keep open/click tracking turned OFF, and skip the unsubscribe link. If you’re going to remove the unsubscribe link, your emails should be of a non-commercial nature.

If your email still didn’t get delivered, then something is very strange, because now the GMass button is acting equivalently to the Gmail Send button, and we already know that the Gmail Send button is successfully delivering your email, otherwise you wouldn’t be here at Step 2. Proceed to Step 3.

Step 3: Looking at IP address and other issues

If your email still isn’t delivering, then the cause could be one of the following:

  • Are you using GMass with an external SMTP service? If so, the delivery issue could be because of the IP address of the SMTP server.
  • Send your email to a Gmail or a G Suite address. If it’s going to the Spam folder, open that email up from the Spam folder and examine the reason that Gmail gives for the spam issue. Sometimes Gmail will tell you outright that it’s the from address or the DKIM-signing-domain that is the reason for the block.
  • If you’re using GMass and sending via Gmail and not an external SMTP service, the receiver could be detecting that the Gmail API is being used rather than native Gmail. GMass makes use of the Gmail API for most of its functionality. This would be an extremely rare scenario, but there is a header that gets inserted into an email sent by GMass, versus the native Gmail Send button, that reveals that the Gmail API is being used.

10 Replies to “How to determine the cause of a spam folder or email blocking issue”

  1. Chris


    Could I use GMass for small (500 at a time each day) segment follow ups of my ecommerce sales campaigns from my other esp. to ensure optimum delivery?

  2. Jason D Jones

    I’m about to cancel your service, none of my emails are going through and the continue to go to spam. I’ve followed all the instruction on how to deal with this and nothing is helping. Can anyone help me besides telling to go to a link for answers?

    My email continues to go to my spam folder and I’m using sendgrid. I’ve followed your instructions on this page. If your answer is to send me to another link then I’m going to cancel your service.

  3. Josh

    I’m having an issue where most of my emails are not delivered because of “DKIM signature not valid” I am using SendGrid, and a dedicated tracking domain. Can you please help

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