Thousands of broadband users across the UK, Germany and the US have had their Internet connection disabled by a security update, a report from The Herald said.
AOL members who were online at the time and using Norton products saw their connection drop and were then unable to reconnect, the report said
"It appears to be an issue with a LiveUpdate patch which Norton sent out overnight for its Norton Firewall product," the report quoted an AOL spokesman as saying.
"It isn't software which AOL has any connection with, so we are in Norton's hands but are working with them to speed things along. It is accurate to estimate the number affected would be in thousands because we have had around 4,000 calls to our UK call center," the official added.
A spokesman for Symantec, which produced Norton products, said a "Symantec intrusion detection signature" in its March 15 LiveUpdate had caused the problem, the report said.