Welcome back to the Community, @IronCoreGym - 

It sounds like some of your customers have unsubscribed or have not opted in to receive marketing emails from your business. 

You can check the status of this under the Customer's profile in your Directory. 

Go to your Dashboard > Customer > Select your Current Member Group > Pick a customer > Scroll down to Marketing for their current status. 

Please let me know if you have any other questions.