Hey @olena r​! Daniel from Customer Support Engineering here 🔧 

It looks like your screenshot was deleted - do you think you could repost it? 😊 When you see this issue, it's because you're sending an email to unsubscribed users that isn't eligible to be sent to them. There are additional rules about emailing unsubscribed users to prevent them from receiving spam. At the moment, you can only email an unsubscribed user as part of a fixed audience, so that this is not a mass email that users continually match, but a one-off email that the unsubscribed user(s) is required to receive. An example of this would be something like a confirmation, news update, or a receipt. Any emails that have a dynamic audience cannot include these users.

Hope this helps 😁