I sent out a mass email this morning, complete with a suppression list. However, people on the suppression list still received the email. I've never had this happen before. Any ideas of what might have happened?
Check your recipient list.
Search the recipient list for the email addresses in question - I expect you will find duplicates of the email addresses in your recipient list.
Fun fact - this means there are multiple "versions" of your prospects. Each one has a unique ID - generally you have duplicate Leads, or duplicate Contacts, and the fact that each has a unique salesforce ID means they're treated as separate individuals.
And the suppression list only included *one* of those versions.
The other versions were fair game, because they weren't on the suppression list (not an exact match by ID number).
Side rant - this is why duplicates are the bane of every marketer's existence, and sales teams who insist they want new Leads to work from every time drive me up the wall.
The best thing you can do is merge the records in Salesforce. Don't delete - merge them. If you have Leads and duplicate Contacts, you want to convert the Lead and merge them into the Contact.
Pardot will follow what you do in Salesforce and also merge them.
If that's not possible then you need to make more extensive (more complicated) suppression lists, to capture all the "versions" of everyone.
