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Deliverability

Tips and strategies to ensure your email reaches its destination.

DKIM pass, bounce anyway? Outlook's new mystery rejection

Over the past few weeks, a rising number of Mailgun customers (and industry peers across other ESPs) have encountered bounce messages. In short:

DKIM appears to pass in one place (like Gmail or your DMARC reports) but fails at Microsoft.

And when it fails, Outlook blocks the message, even if it meets standard DMARC policy of p=none...

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Email authentication: Your ID card for sending

Email authentication lets mailbox providers know that you’re a trusted sender – that you are who you say you are. As a Technical Account Manager at Mailgun, I’m constantly...

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Transactional email vs. Marketing email: Everything you need to know

Imagine this scenario — you’re a sender that is sending massive amounts of email left and right from the same domain without a care in the world about your reputation. Maybe...

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Make things easy with email list management best practices

As an email service provider (ESP) we know how layered the email world can be. To be a successful sender, you must master everything from email deliverability, to ROI, email...

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Microsoft Outlooks new sender requirements: What you need to do by May 5

If you thought you were finally getting a break from the sender requirement conversation after the industry shift brought by Google and Yahoo last year, not quite. Microsoft is stepping up to the plate. In its April 2, blog, Microsoft announced new...

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Why is Gmail blocking my emails? How to prevent it

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...

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The basics of SPF records

SPF doesn’t refer to how long you can wait before you have to reapply your sunblock (seriously, go get some). Instead, the term “SPF” refers to a security measure that helps...

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What are SMTP commands and what do you need to know about them?

Why do we need SMTP commands and what do they do? Well, we use SMTP (Simple Mail Transfer Protocol) commands to communicate with email servers. These commands are...

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How to implement DMARC – A step-by-step guide

Email spoofing is rampant across the internet. Fraudulent emails come in the form of scams, ransomware, and even stock-market manipulation. We see companies lose...

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