In this article, you will learn why your contacts are marked as missing data and what to do about it if you want to change their status.
If contacts in a sequence are set to Missing data, it means that they are missing data for the variable that you used in the Steps templates. The variable pulls the data from a prospect's profile and, if the field connected to this variable is empty, the system will mark the contact as missing data and block them from receiving the sequence.
You can check which variables are missing in the sequence Preview tab:
To make your prospects active, simply add missing data to prospect profiles (or remove variables from the templates), select all people with invalid status on the People page > set status to Active, and your sequence will start sending: