AT&T resolves outage that left some customers without service across the US

AT&T has resolved an outage that affected some customers on Tuesday. The company identified an interoperability issue between carriers that prevented customers from completing calls. The problem has been resolved after collaboration with the other carrier. The number of impacted customers was not disclosed, but there was a significant increase in reported incidents around 1 pm ET, which later declined. The cities with the most reports of issues were listed as New York City, Chicago, Philadelphia, Dallas, Pittsburgh, and Indianapolis. Some Verizon customers also experienced a service outage. AT&T clarified that despite alerts on social media, 911 calls were not disrupted during the outage. AT&T is investigating the accidental triggering of alerts that mentioned disruption to 911 calls. This outage follows a previous disruption in February and a hacking incident in March where customer data was stolen. The story has been updated with additional developments and context.