Firewall to Deter Cyberattacks Blamed for Massachusetts 911 Outage

This alert screen, seen on a mobile phone in Providence, Rhode Island, shows a notification alerting users that the 9-1-1 emergency system is currently down. Michelle Smith/AP Photo

BOSTON—A firewall designed to prevent cyberattacks and hacking was to blame for the 911 outage that hit Massachusetts this week, state officials said Wednesday.

Massachusetts’ 911 system was down for about two hours Tuesday, making it impossible for anyone to reach emergency services using the emergency number.