AT&T says it will give customers a $5 credit after service outage. Here's how to get it.

AT&T said it will provide a $5 credit to customers who were "potentially impacted" by Thursday's widespread network outage, when tens of thousands of customers reported losing cellphone service for much of the day.

In a letter sent Sunday to AT&T employees, CEO John Stankey said the $5 credit is the cost of "essentially a full day of service."

The carrier apologized to customers for the disruption, which the company said was "due to the application and execution of an incorrect process used while working to expand our network, not a cyber attack."