{"id":23386,"date":"2023-09-06T23:56:20","date_gmt":"2023-09-06T23:56:20","guid":{"rendered":"https:\/\/www.gmass.co\/blog\/?p=23386"},"modified":"2025-02-18T00:16:50","modified_gmt":"2025-02-18T00:16:50","slug":"mimecast-blocks","status":"publish","type":"post","link":"https:\/\/www.gmass.co\/blog\/mimecast-blocks\/","title":{"rendered":"How to Get Around Mimecast Blocks"},"content":{"rendered":"

So\u2026 you sent an email campaign. And you got a block bounce notification<\/strong>\u00a0from one or more recipients \u2014 because they use Mimecast<\/strong>, which blocked your message.<\/p>\n

\"A<\/a><\/figure>\n

It happens.<\/p>\n

The Mimecast bounce code<\/a>\u00a0\u2014 554 Email rejected due to security policies - https:\/\/community.mimecast.com\/docs\/DOC-1369#554<\/code>\u00a0\u2014 among other Mimecast-related bounces are a common but unwelcome sight for email senders everywhere.<\/p>\n

Mimecast\u2019s email security filtering is aggressive<\/strong>\u00a0\u2014 extremely<\/em> aggressive.<\/p>\n

But\u2026 with its hair trigger, Mimecast also winds up blocking plenty of legitimate emails too<\/strong>.<\/p>\n

Including the ones you send.<\/p>\n

In this article, I\u2019ll cover the steps you can take to get your emails delivered when Mimecast starts blocking you<\/strong>.<\/p>\n

I\u2019ll also cover how to use GMass\u2019s delivery routes<\/strong> feature to help get messages to Mimecast users without having to sacrifice the settings you want for your campaign<\/strong>.<\/p>\n

And finally, I\u2019ll work really hard not to accidentally type \u201cMinecraft\u201d instead of \u201cMimecast,\u201d which I\u2019ve already almost done six times. As far as I know, Minecraft isn\u2019t bouncing emails. Though, like Mimecast, it\u2019s also an empire built with blocks\u2026<\/p>\n

Mimecast Blocks: Table of Contents<\/h2>\n
    \n
  • What Does Mimecast Do?<\/a><\/li>\n
  • What to Do If You\u2019re a Mimecast Blocked Sender<\/a>\n
      \n
    • 1. Try turning off open and click tracking \u2014 or setting up a custom tracking domain<\/a><\/li>\n
    • 2. Change your IP by switching between Gmail\/SMTP or resending<\/a><\/li>\n
    • 3. Appeal your case with Mimecast (here’s how)<\/a><\/li>\n<\/ul>\n<\/li>\n
    • Getting Around Mimecast Blocks: Takeaways and Next Steps<\/a><\/li>\n<\/ul>\n

      What Does Mimecast Do?<\/h2>\n

      Mimecast is an email security and filtering company that some companies use as their first line of defense against spam, phishing, and malware.<\/p>\n

      Every email provider already has some spam and phishing filter \u2014 Gmail and Google Workspace have a filter that does a really<\/em>\u00a0good job. But some companies want more<\/strong>, so they turn to Mimecast (or one of the others, like Barracuda or Sophos).<\/p>\n

      Mimecast is known in email marketing circles for being particularly aggressive. In fact, it blocks most emails that have any open tracking pixel or a URL with click tracking<\/strong>.<\/p>\n

      We have a history with Mimecast here at GMass. You can read about it in this Twitter thread but, in brief, we included them in our Inbox vs. Spam testing tool<\/a>\u00a0for a while \u2014 until they noticed a few years ago and decided to shut that down.<\/p>\n

      \n

      Let’s talk about Mimecast.<\/p>\n

      Mimecast is an email filter that some companies use in front of Google Workspace. What does that mean?<\/p>\n

      \u2014 Ajay Goel (@PartTimeSnob) September 6, 2023<\/a><\/p><\/blockquote>\n