Email deliverability is an assessment of your sending practices and reputation, and it is the key factor that determines if inbox service providers deliver your email to recipient inboxes. Neglecting email sending best practices will result in email deliverability issues.
For example, the below is a common hard bounce code from Microsoft email servers:
smtp;550 5.7.1 Unfortunately, messages from [###.###.###.#] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors.
This type of bounce is a symptom of not following email sending best practices, and is not the cause of deliverability issues. Microsoft evaluates senders based on more than just the sending IP. If the underlying sending behavior is not changed, the bounces are likely to happen again even if Microsoft chooses to unblock the IP address.
Set up email authentication methods for your domain (SPF, DKIM, and DMARC).
Please reference this knowledge article for additional information on authenticated emails for Marketing Cloud. At a high level, Marketing Cloud takes care of SPF/DKIM once your domain is authenticated, but you will need to configure their own DMARC record separately (Marketing Cloud provides a suggested DMARC record, but work with your IT team to determine the appropriate DMARC record for your organization).
Failure to configure one or more of these would almost likely lead to deliverability issues. You can review email headers from a Marketing Cloud email to confirm all authentication methods pass (see instructions for retrieving email headers for various inbox providers). Alternatively, 3rd-party tools such as aboutmy.email or mail-tester.com can be used for analysis.
A healthy database contains a growing list of engaged recipients. When your database is clean, you can focus on marketing to the most qualified recipients.
Ensure subscribers have opted-in and are engaging regularly.
Consider removing subscribers that have been inactive for over a year.
When importing email addresses into Marketing Cloud Next from a different system, consider only importing email addresses that have never bounced/unsubscribed and have had meaningful interactions with your email in the past year.
Sending to previously bounced email addresses will only harm your domain’s reputation and increase the likelihood of being blocked by inbox service providers (ISPs). Switching marketing platforms will not make these email addresses more deliverable.
Sending to previously unsubscribed email addresses could increase the potential for spam complaints.
Set reminders to conduct a regular hygiene check-up to protect your sending reputation.
Do not use email addresses from a purchased list.
Consider using a confirmed opt-in process for net new recipients/email addresses.
Reminder that harming your sending reputation will eventually impact even your most highly engaged/qualified recipients and potentially prevent you from landing email into their inboxes.
To build a strong sender reputation and maintain reliable email delivery, gradually increase the volume and frequency of your email sends and avoid spikes in email volume.
If you’re using a brand new domain or recently started using Marketing Cloud, your domain is not immediately recognized by inbox service providers (ISPs) and starts with a reputation of zero/unknown. ISPs are increasingly prioritizing domain reputation in addition to IP reputation.
Warm up your domain by sending a small number of emails first to your most engaged subscribers. You can use the domain warming schedule outlined in this knowledge article.
Include a prominent unsubscribe link that makes opting out easy. Avoid hiding unsubscribe functions behind a login.
Mail testing tools (such as mail-tester.com) can give content optimization hints.
Include a physical contact address to comply with the CAN-SPAM law.
Note: some of these resources may reference other Marketing Cloud products (such as Marketing Cloud Engagement or Marketing Cloud Account Engagement). The content is relevant because email deliverability best practices are applicable to any email platforms.
Knowledge Article: Authenticating Marketing Cloud Emails
Knowledge Article: Bulk Sender Guidelines for Marketing Cloud
Knowledge Article: Marketing Cloud Email Bounce Management
Knowledge Article: Marketing Cloud Next Understanding Spam Complaints
Salesforce Blog: Email Authentication
Salesforce Blog: Need An Email Engagement Boost? Expert Advice From Trailblazers
Salesforce Blog: B2B Email Marketing Best Practices: What You Need To Know Now
Salesforce Blog: Email Unsubscribe Rates on the Rise
Salesforce: Email deliverability: a complete guide
Trailhead: Email Deliverability Essentials
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