Help CenterRecur360 uses SendGrid to send emails. If a customers email shows as "Dropped" in Recur360 you can research in SendGrid to find out the cause of the drop.
It is possible that the customer marked the email as spam. If they did we will no longer try to send emails to that email address.
some email providers like yahoo report to Sendgrid when a person marks an email as spam. People doing that hurts our email reputation (making it more likely our emails will auto-go to spam for other recipients in the future), so if Sendgrid receives a report that someone spammed something it moves their email address to a list where Sendgrid stops emailing them so our reputation doesn’t get hurt further by them. We can have Sendgrid email them again, but may still go direct to their spam now that they’ve marked it as such.