When I try to manually add certain patients to a custom campaign, their names are grayed out and I'm unable to click on them. Why?

In the "Recipients" step of a custom campaign, you have the ability to manually add a patient to your recipients list by typing in and clicking on their name. 

For patients who cannot be added to the list, their names will be grayed out. There are three reasons a patient cannot be added:

1. The campaign uses emails or text messages and the patient doesn't have an email or cell number on file.

2. The patient is inactive. 

3. The patient is already included in the list of recipients.