Even when a customer has been enrolled it is still possible for a SMS or Push Message to be sent, but not be successfully delivered. This can be caused by SMS Gateway issues, or mobile numbers becoming invalid over time. As a result of this, it’s also possible for the number of customers who were contacted to be lower than the number of customers enrolled.
In the example image provided below, we can see that while the campaign initiator was prepared to communicate with a maximum of 4,355 customers, by the time the campaign started to enroll customers, only 3,959 were still eligible to be communicated with, and of these, only 3,779 actually received the SMS and/or Push message.