We have never ever had such a low deliverability rate (8%) on any of emails before, granted there are still a lot of emails that are pending.
With that said, I'm confused and concerned because the smart list that we sent to had the following filters:
Unsubscribed is false
Email Invalid is false
Blacklisted is false
So I'm almost certain it is NOT a smart list issue.
I am using a subject line test in the email that was sent. But I'm not sure how or why this would affect deliverability either.
Does anyone have any insight?