You work hard to create emails that engage with your customers or audience, so it can be very frustrating to learn that some recipients never received your email during an email delivery failure.

Despite the fact that your customers request and agree to receive your emails, Internet Service Providers (ISPs—like Gmail, Yahoo, and AOL) and other filters can make can make 22% of them go undelivered. What’s a sender to do?

First of all, it’s important to understand that it’s not personal. ISPs are just trying to sift through over 100 billion emails that are sent daily.

This volume of spam makes it extremely difficult for ISPs to determine which mail streams are legitimate and which ones are just trying to dupe customers.

Add in bad actors, such as phishers and spoofers, to the mix and deciphering the email delivery matrix becomes even trickier. Therefore, it’s important that you follow email best practices so you can help ISPs better identify your mail as legitimate. Here are three tips to help you do just that.

1. Zero Out Your Complaint Box

A high complaint rate is one of the tops reasons that your email will end up in the spam/junk folder or put your IP on a deny list. Complaints are registered when a user marks your email message as spam (by hitting the “Report Spam” button).

Each ISP has a threshold for spam complaints and if your email campaign crosses the line, your emails will never make it to your user. This is because ISPs are adamant about their customers only receiving wanted email.

You can avoid this problem by signing up for feedback loops. Feedback loops arm you with the email addresses that complained about your email so that you can swiftly remove them from your list.

You can even automate this function like TeamSnap did so you can easily maintain a clean, healthy list devoid of complainers.

2. Shore Up Your Infrastructure

Building your own email infrastructure can be complex and expensive, requiring dedicated resources and servers. While many companies opt to maintain their own mail servers, an incorrect configuration can put a halt to your email delivery plans. This is, in part, because spammers tend to focus on sending malicious email, not so much on making sure their email servers are in proper working order.

Also be sure to follow a few rules of thumb when sending from your own servers. These include sending from a dedicated IP address if you are sending high volumes of email, setting up “postmaster” and “abuse” mailboxes for your domain that you monitor regularly, and ensuring your servers are secure.

Also, avoid open relays or open proxies for maximum email security. Alternatively, you could work directly with an email service provider to avoid the complexities of maintaining your own server.

3. Always Ask For Permission

Good (or bad) email delivery always starts in the same place—with your email list. A good list is built based on strong permission standards. A strong opt-in strategy will go a long way in building an engaged audience.

However, just because you got permission once, doesn’t mean this permission lasts for a lifetime. User needs change over time, and you’ll need to compensate for list fatigue and poor response rates as a result.

Here are some tips and best practices to maintain good email delivery rates:

ISPs now pay close attention to engagement rates, so you need your users to regularly open and click on your emails. Here are some tips and best practices to maintain good email delivery rates:

  • Systematically weed out your non-responders by asking for permission to continue emailing them.
  • Periodically ask your users to update their preferences in your preference center.
  • Be sure your unsubscribe functionality is working properly and easily found too.

In the end, it’s better for users to proactively remove themselves from your list then to go dormant or report you as spam. The latter sends red flags to the ISPs, which can create problems for your email program. For more tips, check out our free guide on How to Authentically Grow Your Email List.


These three tips above will help ensure higher delivery rates and reduce the cases of email delivery failure to your email list. You’ll still need to closely monitor your email reputation, but if you focus heavily on avoiding complaints, maintaining a solid email infrastructure, and developing an ongoing permission strategy, you’re winning more than half the battle.

To learn more about email deliverability best practices and how to comply with ISPs, download our 2019 Email Deliverability Guide.


With more than 15 years of experience, Carly Brantz is an email deliverability and inbound marketing veteran. As the VP of Revenue Marketing at SendGrid, Carly empowers her team to transform marketing from a cost center to a revenue generator. With a key focus on funnel optimization, Carly leads the team responsible for content creation, lead nurturing, SEO/SEM, and website optimization. An accomplished speaker, Carly shares her email delivery and revenue marketing tactics as a headline speaker on SendGrid’s international roadshow as well as other Marketing conferences.