Only 5% Marketing Campaign Delivery

After sending out a scheduled campaigned, we received this message stating that only 5% of our emails were delivered. This is using Shopify’s built in email campaign system. There were no details provided and when you click on “View delivery details” it only displays the analytics of the email sent. Does anyone have any insight as to what would prevent deliveries?

Take a look at this article and see if you are following email deliverability best practices