Email deliverability is the ability to land emails in the inbox of your recipients. If your campaign's deliverability takes a hit, it might be due to certain email marketing practices you follow. Let's dive deep and learn about practices that affect email deliverability.

The best way to secure inbox placement is by ensuring that your emails don't look suspicious in the eyes of mailbox providers and anti-spam services. Major mailbox providers consider emails from an unauthenticated sender domain to be suspicious. If you send emails from an unauthenticated sender domain, inbox placement may be denied, and sometimes the emails may land in the spam folder.

So, we strongly urge our users to authenticate their sender domain before sending email campaigns. Authenticating your sender domain not only earns a positive reputation from mailbox providers and anti-spam services but also improves email deliverability. We recommend our users implement SPF, DKIM, and DMARC as they are the most efficient email authentication mechanisms.

Learn more about authenticating your sender domain.

The reputations of your sender domain and IP address impact email deliverability to a great extent. Receiving servers of mailbox providers assess the reputations of the sender domain and IP address to make inbox decisions. The quality of your mailing list, your email sending practices, and the email content directly impact the reputation your sender domain earns. If the quality of your mailing list is poor, your emails will bounce and you will receive complaints and unsubscribes.

This will earn a negative reputation for your sender domain/IP address. If you adopt unhygienic email sending practices, and if the email content is spammy, your sender domain/IP address will also earn a negative reputation. If you use an IP address and sender domain that have a negative reputation to send emails, the receiving servers of mailbox providers will either reject your emails or place them in the spam folder. If you decide to use a new sender domain, we recommend you warm it up before sending a huge volume of emails.

Learn more about warming up your sender domain.

Some of the major email service providers have framed policies that mandate the implementation of DMARC. If you don't authenticate your sender domain by implementing DMARC, your emails will bounce. This implies that you can't use third-party sender domains. Hence we don't recommend sending marketing emails from a public domain sender address as you can't authenticate public sender domains.

One of the major challenges for marketers is to grow and manage their mailing list. When they don't adopt hygienic list management techniques and instead purchase mailing lists, the quality of the mailing list will be poor. If the quality of the mailing list is poor, your campaigns will face deliverability issues and you will not be able to achieve your conversion goals. Let's dive a little deeper into this subject.

At Zoho Campaigns, we strongly urge our users not to use purchased mailing lists. When you purchase mailing lists and send emails to them, your emails will bounce, hit spam traps, and receive spam markings. This will incur a negative reputation for your sender domain and IP address.

When marketers use the single opt-in technique, it increases the chances that invalid and incorrect email addresses will enter your mailing lists. If you send emails to a mailing list with these, your emails may bounce or hit spam traps. If a lot of your emails bounce, it will incur a negative reputation from mailbox providers. If your emails reach people who didn't subscribe to receive your emails, they might mark it as spam.

At Zoho Campaigns we always urge our users to grow their mailing lists organically by using the double opt-in technique. This technique prevents incorrect and invalid email addresses from entering your mailing lists. Only contacts interested in receiving your emails will enter your mailing lists, because recipients will be sent a follow-up email in which they'll have to verify their interest in receiving emails from you. This will help you hit your conversion goals and grow a solid customer base.

If your mailing list contains a lot of inactive contacts, your campaign performance will be affected. We always recommend our users identify inactive contacts and win them back by sending re-engagement campaigns. While crafting re-engagement campaigns, use attractive subject lines, list the benefits of staying on your mailing list, offer discounts, and ask the contacts if they are interested in receiving your emails. You can retain contacts who decided to stay on your mailing list and remove contacts who didn't respond to your re-engagement campaign.

Mailbox providers give weightage to email engagement when making inbox decisions. They prefer offering inbox placement to businesses whose emails are always read. This implies that for your emails to land in the inbox, you should keep your contacts engaged.

If you offer content that's irrelevant to your contact's needs and interests, they might not open your emails. If a lot of your contacts don't open your emails or negatively engage with them, mailbox providers may assume that their users are not interested in receiving your emails. They might even decide not to offer inbox placement for your future emails. 

Learn more ways to keep your contacts engaged.

The receiving servers of mailbox providers scan the content in an email before offering inbox placement. A receiving server will reject emails or place them in the spam folder when the email has spam phrases and suspicious URLs.

When the email message has spam phrases, the receiving server will definitely deny inbox placement. We urge our users to avoid spam phrases while crafting email messages.

Spammers mostly use shortened urls and urls with multiple redirects to perform malicious activities. While scanning your email's content, if the receiving server finds the campaign contains shortened URLs, blacklisted URLs, broken or invalid URLs, and URLs with multiple redirects, they might deny inbox placement and place your emails in the spam folder. 

Apart from the sender domain, IP address, and content, your email sending practices will also impact email deliverability.

The receiving servers of mailbox providers have set a threshold value for the emails they receive per day. If you suddenly amp up the email volume and continue sending a huge volume of emails over a period, the receiving servers may reject your emails as the email volume would have reached the threshold value. To avoid this, we always urge our users to split the email volume into multiple batches and send them after frequent intervals. This will ensure that the receiving servers don't reject your emails.

At Zoho Campaigns, we have a feature for sending campaigns in batches. Learn more about this feature.

Sending emails during the wee hours of the morning might irk some of your contacts, and they might even unsubscribe. Not sending emails at an ideal time could also mean your emails get buried in your contact's inbox and might be left unopened, which will affect email engagement. If your contacts unsubscribe or leave your emails unopened, mailbox providers might assume that their users are not interested in your emails and they might deny inbox placement for your future emails.

So we recommend our users analyze the recipient's time zone and send emails accordingly. Also, it is advisable to identify the time when your contacts are likely to check their mailbox and send emails during that time to ensure maximum email engagement. At Zoho Campaigns, we have a feature to send campaigns according to the recipient's optimal open time.

Sometimes marketers tend to believe that regularly sending newsletters and the occasional email campaign will help them hit their conversion goals. This perception is wrong in every possible way. To maximize your conversions, you must constantly nurture your contacts and keep them engaged by offering content relevant to their needs and interests. We also urge our users not to send too many campaigns in a week. If you flood your contact's inbox with your emails, it might irk them and they might mark your emails as spam or even unsubscribe. We recommend that our users maintain an optimal email frequency.

At Zoho Campaigns, we urge our users not to send image-only campaigns or campaigns with too many images. This is because when email clients disable the auto-download of images, the images in your campaigns will not be downloaded until recipients click the display images option. In such situations, you will not be able to convey the message you want. 

After sending a campaign, we recommend our users monitor the performance of the campaign to understand what went right and wrong. Sometimes the emails you sent will have bounced or may have received spam markings and unsubscribes. We urge our users to analyze the reasons for these issues and take necessary corrective measures. 

Email bounces and negative engagement will earn a negative reputation for the sender domain and IP address from mailbox providers and anti-spam services. If you leave the issue unresolved, it might reoccur and further dent the reputation of the sender domain and IP address and lead to deliverability issues for your future emails.

When mailbox providers reject an email, classify it as as spam, and offer inbox placement, they send signals on what kind of emails they like to receive and how they like to receive them. You can achieve email deliverability when you interpret these signals, formulate your email marketing strategies around them, and adopt hygienic email sending practices.