I didn't think much of it at first, but after sending several mass emails through NXT, I noticed there were some people that should have received an email, but didn't.

After contacting customer support, I was given two explanations:

1.) There's someone in the email list that has a duplicate email of someone else on that list

2.) The email is "Blocklisted" by Blackbaud after determining that it is a bad email.

-More info on "Blocklisted" here: https://kb.blackbaud.com/knowledgebase/articles/Article/44027

Blocklisted emails are not marked in the system in any way. This means that someone could have what appears to be a 'good' email in the system, but they never actually receive anything because Blackbaud has "Blocklisted" it. You as an administrator or fundraiser would never know it was a bad email.

Blackbaud needs to implement a section in the NXT email service that shows us which emails in the list are "Blocklisted", similar to how we can see Bounces and Unsubscribes.

To use an example, I just sent out a mass email which did not make it to 2,169 people. Some didn't get it because they had no email, some because they had duplicates. 366 of them didn't receive it because their email was "Blocklisted" by Blackbaud. These 366 will keep showing on my lists/queries as valid emails. Nothing is done to mark them as bad/unused and you, as a user of Raiser's Edge, have no way of knowing who falls under this category without speaking to customer support.