Improving the quality of your subscriber list
Managing who does and who does not receive your email marketing is a good way to increase engagement, which in turn has an impact on the delivery and batching success rate of your emails. If you want to send email campaigns that are tailored to a specific set of customers, then you can create a customer segment. To edit individual customers profiles, click their name on the Customers page in your Shopify admin.
Remove a subscriber from your subscriber list
From your Shopify admin, click Customers.
Search for the customer, and then click the customer's name to open their profile.
In the Email Marketing section, click Edit status.
Uncheck Customer agreed to receive marketing emails.
If a customer clicks Unsubscribe in an email from you, or marks the email as spam, then they'll be automatically and immediately removed from your list.
If an email address bounces back, then that email address is not included in future email marketing email campaigns.
Emails stopped delivering
The delivery system might stop delivering an email message if subscriber engagement is low or if there are other negative performance indicators to protect your sender reputation and to ensure that future email messages are delivered.
There are several factors that might have a negative affect on an email's performance.
List quality and high bounce rates
Low-quality subscriber lists can often result in high bounce rates, which in turn have a negative impact on the deliverability of your emails.
When an incorrect or nonexistent email messages prevent a message from being delivered, then the corresponding email address is removed from the subscriber list automatically. Before you import a list of email addresses, review the address list and fix any typos or errors.
Low open rate
Send your emails at a time that makes sense for your subscribers. You can compose an email in advance, and then schedule the email to go out at a time that you think it's more likely to be opened by your subscribers.
Verify that the subject line of the email is accurate, concise, and compelling.
High number of unsubscribes or frequently flagged as spam
When subscribers manually mark your messages as spam, the delivery system might stop delivering your messages. This often occurs when the recipients didn't explicitly subscribe to your email marketing. Enable double opt-in to help ensure that your subscribers want to receive your emails.