We are using Shopify Email for newsletter campaigns. We have about 7000 subscribers and average a 70% open rate.
We keep getting this error message "There are errors in your campaign that may cause problems with publishing" upon sending emails, and then only 90% of my emails are actually delivered. However, there is no further information, or error codes, that would allow me to rectify the issue. It just routes me to the general Shopify information page on how to send a high quality email, which I am following.