A flaw in Time Warner Cable's (TWC) network knocked out the internet service of about 12 million of the overall 14.5 million customers in 29 US states, on early hours of 27th August.
Claiming an issue in the internet backbone during regular network maintenance caused outage, Time Warner noted that most of the internet subscribers were back online within four hours from the shutdown.
A TWC spokesman told the BBC: "During an overnight network maintenance activity in which we were managing IP [internet protocol] addresses, an erroneous configuration was propagated throughout our national backbone, resulting in a network outage.
"We immediately identified and corrected the root cause of the issue and restored service by 07.30 ET.
"We apologise for any inconvenience this caused our customers. A failure of this size is very serious and we are taking the necessary steps to improve our processes with the objective of making sure this doesn't happen again."
However, the company claimed that its services have now been restored following a nationwide outage.
Further, the Federal Communications Commission (FCC) has ordered TWC to pay a fine over failing to report the network disruption in a welltimed manner.
TWC has settled the issue by agreeing to shell out $1.1m (£660,000) in fines as well as execute a three-year compliance scheme.