Time Warner Cable, which serves about 14.5 million of the country's 115 million homes, said the outage occurred at 4:30 a.m. ET "during our routine network maintenance."
"An issue with our Internet backbone created disruption with our Internet and On Demand services," the company said in a statement.
Earlier this year, the American Consumer Satisfaction Index showed Time Warner Cable had the lowest satisfaction rate of any big television provider.
Comcast (CCV), the company with the second-lowest satisfaction rate in that survey, is in the process of acquiring Time Warner Cable.
Both companies have made big investments to improve customer service and the quality of their products -- but of course none of that matters when customers wake up and find out the Internet is not working.
Many of those homes are in big metropolitan areas like New York City and Los Angeles. That made Wednesday's outage more noticeable, because it affected journalists and the people who employ them.