Comcast customers were without Internet service for about five hours starting at 7:30 p.m. Sunday night.
The Internet outage affected those in the Chicago area, northwest Indiana and southwest Michigan, Comcast spokeswoman Angelynne Amores said. She said the outage did not affect cable or phone service.
She said the company’s engineers are still investigating the outage, and as of Monday, a cause had not yet been determined.
She said there were a number of customer calls to Comcast, and she said information and updates are provided there during an outage.
“Typically, we have a message on the 800 number when you call,” Amores said.