14 Real Tips to Avoid Email Deliverability Issues

Real Tips to Avoid Deliverability Issues

You spend a lot of time designing a beautiful branded email template, polishing up your email copy, and crafting a teasing and enticing subject line that should skyrocket your email open and click-through rate. But before pressing the Send button, did you think that your subscribers might not even get the opportunity to see your email?

Thus, it’s always a good idea to use an email spam checker and test your email spam score and placement at different mailbox providers before sending a real email campaign. The results may be surprising.

No matter how good your email list is and how legitimate email marketer you are, there are a lot of things out there that may not allow your email to land in the recipient’s Inbox. And with more rigorous and increasingly advanced filtering systems, it’s to your advantage to be warned about everything that influences your email deliverability.

In this post, we take a look at the things you should absolutely NOT do if you want to succeed in email marketing and the things you can proactively DO to increase your Inbox Placement rate.

Plus, we included a real-time email deliverability test so that you can instantly see what Inbox placement and spam placement rate you can expect and what issues you should address if your deliverability suffers.

Just keep reading…

Below we present an exhaustive list of do’s and don’ts that will be valuable not only for beginners in the email marketing niche, but for professionals with many years of experience as well.

10 Things NOT to Do If You Want to Send to Inbox

Let’s start from the big “don’t” in email marketing that every good marketer should remember like a, b, c. Here they are:

  1. Don’t: Buy or Rent Email Lists

    You can’t be sure of the quality of such lists. The selling company may tell you that those people agreed to email communications, but they did not give explicit permission to YOU to send them emails. It is increasing the potential they will mark your messages as spam.

  2. Don’t: Harvest Emails on the Websites

    This is always illegal and… dangerous. You can scrape spam traps that are not intended to receive any emails, but only to identify spammers. Hitting a spam trap is fraught with serious consequences including blacklisting of your sending IP address and bad sender reputation.

  3. Don’t: Send from a “No-Reply” Email Address

    It’s not illegal, but it’s a bad email marketing practice that hurts your deliverability. Some ISPs, network spam filters, and customers’ personal email security settings are set up to move messages with “no-reply” addresses to the junk folder.

    It’s also a question of ethics. By not allowing the recipients to reply to your email campaigns, it makes you look like you don’t care about your recipients. It’s a one gate play when you can blast them with emails and they can not communicate back. It increases the likelihood of reporting your email as spam.

  4. Don’t: Send from a Free Domain

    Free domains, like Gmail, Yahoo!, Outlook and others, are bad for email marketing purposes for many reasons. Firstly, you won’t be able to send big volumes of emails from free domains. They are not designed for this purpose. Secondly, deliverability from free domains is rather low, so even if your sending volume is within their range, the amount of emails that will land in the Inbox is very small. Lastly, email campaigns from free domains are most likely to fail passing authentication protocol.

  5. Don’t: Send Email without Authentication

    Security and trust are crucial for 21st-century email marketing. If you don’t have email authentication protocols that ensure legitimacy of your emails, they will be rejected by other ISPs. There are three authentication protocols: SPF, DKIM, and DMARC. Implementing them secures both you and your recipients from email spoofing, phishing and other fraudulent activity.

  6. Don’t: Use a Generic Friendly “From” Name

    It’s always better to have a friendly text in the “From” field rather than a pure email address. But do not use a generic text like “Customer Service”, “Account Verification”, “Sales Department.”

    Always include your brand name: “GlockApps Customer Service”, “GlockApps Account Verification”, “GlockApps Sales Department.” A “From” name without your brand is automatically suspicious.

  7. Don’t: Host Images and Links on Fishy Sites

    It’s always a good idea to upload images and big files to a website and link to them from the email. It decreases the message size, increases the sending speed and the message loading time. But be careful about the sites you upload the files to. The best option is to upload the files and images to your own website that you know is trustworthy.

    But if you don’t have a website or can’t upload data there, you can consider public sites like dropbox. Do not use fishy sites that may be blacklisted. Links and images from blacklisted sites are often a reason why filters block the message.

  8. Don’t: Send an Image-Only Message

    Although the message content has no same impact on deliverability as it had before, it still matters. An email message consisting of images only is always suspicious for anti-spam filters and is likely to be filtered as spam.

    Design your email in a manner that has a good text-to-image ratio, includes both plain text and HTML parts, and has the correct HTML code with no broken tags.

  9. Don’t: Force the Subscribers to Stay on Your List

    Email marketers often do a big mistake trying to retain the subscribers by hiding the unsubscribe link or making the unsubscribe process too complex. But believe me: if someone wants to stop receiving your emails, they will do it any way (most likely by sending a complaint).

    Just take it as a fact: people leave. They can change interests and switch to something else, they may not need your product or service anymore, or they may not like the content you are sending them anymore. Whatever the reason – you will lose subscribers and the best you can do is to respect their decision and make the process as simple as possible.

    To leave a good impression about your brand, you could use a simple unsubscribe confirmation page saying: “We are sorry to see you go, but we respect that. In the future if we change your mind, please remember our site and we will be honored to work with you again.” It will give off a better vibe than asking “Are you sure you want to unsubscribe?” a dozen of times during the unsubscribe process.

  10. Don’t: Send to Bounced, Unsubscribed, and Complained Users

    Make sure your email automation software is not sending to people with invalid addresses repeatedly as it will hurt your sender reputation and will cause deliverability problems in the future. Sending to unsubscribed and complained recipients is a big “no-no.” It will result in more complaints and will cause your IP address to be blacklisted.

    Thus, honor unsubscribe requests and process them on time. Sign up for feedback loops with ISPs that support this service and receive notifications about complaints on your emails. Handle bounce emails and complaints timely and exclude those people from your active mailing list.

So, if you remember the above bad practices and avoid them in your email marketing program, you’ll avoid the spam folder.

Now let’s consider good practices that will help you position yourself as a good sender, maximize your deliverability, and improve your email open rate.

14 Things to DO to Maximize Your Inbox Placements

1. Do: Use a Confirmed Email Opt-In Method

This means that after someone subscribes, you send them an email with a confirmation link they must click to confirm their subscription letting you know they do want to receive email communications from you.

A confirmed opt-in method allows you to proactively exclude invalid and fake email addresses from your list and prevent malicious subscriptions. In addition, it increases the subscriber engagement, which is an important factor for deliverability.

2. Do: Ask the Subscribers to Whitelist Your Email Address

This is one more step to the recipient’s Inbox. Sometimes a legitimate email people want still ends up in the spam box. By asking your subscribers to add your email address to their safe sender list or their address book, you increase the chance for the email to be delivered to the Inbox.

You can send the whitelisting instructions in the welcome message after the subscription and repeat them from time to time in regular newsletters.

3. Do: Use a Recognizable Sender Name

Include your brand name into the sender name so that the recipients can instantly recognize your message. Example: Julia from GlockApps, GlockApps News. Stick to the same sender name over all your marketing emails because the consistency builds recognition and trust into your brand.

Send email marketing emails from your own domain, not from a free domain like gmail.com or yahoo.com. It’s much easier to use the email address you set up with some of the free providers, but sending marketing emails from your own domain can benefit you in a couple of ways:

– “From” fields with free email addresses are more monitored due to the fact that free email addresses are so easy to create and a lot of spammers just get a new address for each mailing.

– There are already ISPs (so far, yahoo.com and aol.com) that do not allow the use of their domain in “From” addresses if the message is sent from a different mail server (DMARC policy).

– “From” address on a private domain looks more trustworthy because it is you who controls the domain and can create or allow someone to create new accounts on it.

– “From” address on a private domain makes you look more professional in the eyes of the recipients (a lot of people do, in fact, look at this).

4. Do: Include a Working Unsubscribe Link

Firstly, the unsubscribe link is required by the CAN-SPAM Act. Secondly, a clear and working unsubscribe link will reduce spam complaints. Place the unsubscribe link in a prominent place so your subscribers can instantly find it and click it if they wish to stop receiving emails from you. Sometimes, complaints happen simply because people can’t find where to click to be removed from the list.

5. Do: Get Rid of the Dead Weight on Your Email List

They don’t open your messages, don’t click the links, don’t do anything on your emails. Almost each list has inactive subscribers who have not engaged with any of your messages for the last year or so. There are two most popular reasons for the subscriber inactivity:

– The email address is not used by a live person anymore.

– Your messages are filtered out by the subscriber’s private settings.

Keeping such subscribers on your list becomes pointless because they only increase your list size without giving any value and force you paying an additional cost needed to maintain and send to your list.

However, before you remove inactive recipients from your list, it’s worth sending them a reconfirmation campaign. Trying to get them back is not a bad thing. Here are some things you need to remember when you plan a reconfirmation campaign:

Give them an additional incentive to stay on your list. Some kind of promotion, maybe a free download, or exclusive coupon or whatever you think will work here. Just remember: if you promise something, you have to follow through.

Include the link to resubscribe. If someone does not see the email and does not reconfirm the subscription before they are removed, they can join your list again in no time. Thus, right under the visible reconfirmation link add clear information about how they can resubscribe to your list if they are already removed.

Sending the reconfirmation campaigns every 3-6 months will keep the high quality of your list, which will also positively impact your email deliverability and ROI.

6. Do: Send Emails in the MIME Format

This means including an HTML and a plain-text version of the email. Not only it tells the filters that your email is legitimate, but it also makes it more reader-friendly.

7. Do: Send Relevant Emails

Irrelevant emails do provoke negative actions such as spam markings, complaints, and deletions without reading which is not good for the sender. You want your subscribers to act positively on your emails because the recipient engagement (opens, clicks, replies, forwards, “not spam” markings) is an essential factor in filtering.

Mailbox providers learn from the user’s actions and start treating future emails from that particular sender accordingly. Thus, your goal is to keep a base of engaged recipients who open, read, and click your emails. So, stick to what you promised on the subscription page and do not bombard your subscribers with irrelevant content.

8. Do: Authenticate Your Emails with SPF, DKIM, and DMARC

All marketing emails should be authenticated. Authentication allows the mailbox provider to confirm that the sender is the one who he pretends to be.

Authentication is essential because it protects your brand against phishing and spoofing, builds your domain reputation, reduces the chances of the messages being filtered or blocked by major mailbox providers, and increases the Inbox Placement rate.

There are four primary methods of authentication: SPF (Sender Policy Framework), Reverse DNS, DKIM, and DMARC.

You can quickly check if your domain is protected with DMARC and SPF using the GlockApps DMARC monitoring tool.

Read this Email Authentication: the Ultimate Guide post for more information about email authentication.

9. Do: Check Your Sender Reputation

Deliverability is impacted heavily by your sender reputation. Mailbox providers monitor your sender reputation and use it as one of the factors to decide whether to deliver or block your emails. If you have a bad sender reputation, you’re minimizing your chances of reaching the Inbox.

The sender reputation can change from campaign to campaign so a regular monitoring of your sender reputation is essential. You can setup an automated process of checking your IPs against blacklists and be alerted via email when the IP got listed in your GlockApps account

If one day you see that your sender reputation has fallen, it might be the time to investigate what went wrong and fix it quickly!

10. Do: Check Your Sending IP Address against Blacklists

Today there are over 300 blacklists, including widely used public lists and privately held ones. Blacklists can be a serious problem on the path of the email to the Inbox.

That’s why it’s important that you monitor your IP address reputation and if you find your IP listed on a blacklist, take time to find out and resolve the root problem that caused you to be blacklisted and then submit a delisting request.

If you do not resolve the problem, you’ll be listed again, and over time your delisting requests can be rejected.

You can use the GlockApps IP reputation monitor to check your IP address against dozens of blacklists on auto-pilot and be notified via email if a listing is observed.

Besides public blacklists, your IP can be blocked by a particular mailbox provider. Mailbox providers are forced to introduce filters and blacklists to protect their users from unsolicited emails. Gmail, Hotmail, Yahoo and other providers maintain blacklists of IPs seen to send spam to their users.

Below are good guides you’ll want to check to learn how to find out if your sending IP is blacklisted by an ISP and how to request the removal:

How to Remove Your IP Address from Gmail’s Blacklist
How to Remove Your IP Address from the Hotmail/Outlook’s Blacklist
How to Remove Your IP Address from the Yahoo!’s Blacklist

11. Do: Signup for Feedback Loops

When a recipient clicks “This is Spam” for the email, it is considered a “complaint.” Many mailbox providers can notify senders when it happens by allowing the sender to sign up for a feedback loop service. Here you can find the links to FBL signup pages for all ISPs that support the service.

After you apply, ISPs will start sending email messages that were reported as spam to your email account that you’ve set up specifically for feedback loops.

The information that you will be sent back is simply a copy of the message including the header and body of the message that the complaining subscriber received. The most popular format that most mailbox providers use is Abuse Reporting Format (ARF).

Now, you can collect any information you want from this message. At the very minimum, extract the recipient’s email address and add it the suppression list.

12. Do: Monitor Your Email Bounce Rates

Bounce rate is the percentage of emails that ‘bounced’ from email addresses (couldn’t be delivered for one of several reasons) in the total amount of emails sent.

High bounce rate indicates problems with mailing list: many inactive or invalid addresses, email blockage, temporarily unavailable address, etc. High bounce rate lowers the sender’s reputation, blacklists your IP, and reduces clients’ engagement level among other negative outcomes.

13. Do: Test and Monitor Your Email Deliverability

After all, deliverability is what email marketing is about. If the recipients do not see your email, you just waste your time and money on designing and sending the most beautiful email in the world.

Like a reputation, deliverability can fluctuate from email to email. You may slightly change the content, send from a new email/domain, or from a new IP, and your Inbox placement rate can go down. Or, you may not change anything at all, but the very same email template can result in more spam placements than it was a month ago simply because the previous campaign has generated complaints or other negative actions.

Doing a regular email deliverability testing, you will identify problems on a proactive basis and will be able to fix them to restore your Inbox rate.

Testing and monitoring email deliverability were a challenge before. You had to set up email accounts with all possible email providers, send a copy of your email to your test addresses and see where it is delivered to.

At present, testing tools like GlockApps make it quick and easy. You simply send your email to the seed list and get your deliverability report within minutes.

So, do not put it off! Use our deliverability testing tool right now to see whether or not you have any deliverability issues.

14. Do: Use an Email Spam Test Tool before Sending

Use an email spam test to cover possible issues before they appear. Some will suggest sending email to your own mailbox to check whether it will be delivered, but this method does not provide correct information and shows results for only one specific ISP.

Email spam test, on the other hand, analyzes your email against many ISPs and includes their filtering specifications to let you know if your message will go past them. It doesn’t matter how well you craft your emails, sometimes there are things you are absolutely oblivious to, that can trigger spam filtering.

Running a spam test on a regular basis improves deliverability, reputation and reduces the amount of spam complaints from your recipients.

Real-Time Email Deliverability and Spam Filtering Test

Testing and monitoring email deliverability using a tool like GlockApps will help you identify potential filtering issues before you send.

Within minutes, GlockApps will show you where your email is placed at different ISPs.

To generate the report, we’ll re-send your email through our personal accounts with Amazon SES, SendGrid, and Mailgun to the control list of email addresses (seed list).

But you should be aware that the deliverability may be different when you send emails through your SMTP server, delivery service or email service provider.

To test deliverability through YOUR sending infrastructure, you’ll need to create an account on GlockApps.

In your personal account, you’ll be able to create new tests and we’ll show you in real-time if there are any problems with YOUR sending system and message.

So, qucik-test your email using the live test below and you’ll find the “Create My Account” button in your quick report.


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Julia Gulevich is an email marketing expert and customer support professional at Geminds LLC with more than 15 years of experience. Author of numerous blog posts, publications, and articles about email marketing and deliverability.