PersistIQ offers safety checks to protect clients from making embarrassing mistakes, such as sending "Hello {{first_name}}" or contacting a prospect who has already unsubscribed.
That is why when you add prospects to the campaign, the safety check will not allow you to override the opt-out status.
You will need to take extra steps to change the opt-out status. You can see an example of how to do so below;
Step-by-step directions:
Go to the "Prospects" tab
Apply the filter "Opted Out" located in the left menu
Find the prospect in question
Under the "status" column change the prospect from "Opted Out" to "Engaged"
Under the "Opted Out" column, change the status by clicking on the "Opted Out" box. The drop-down menu will pop-up and you will have the choice to unselect "Opted Out". Go ahead and do that.
Now when you click on "Add to Campaigns" this prospect will be added to your campaign.