AT&T experienced a major outage that left many customers nationwide unable to make calls, send texts, or access the internet on their mobile devices. The outage began around 4am ET and service was eventually restored by 3pm ET, nearly 11 hours later. While the exact cause is still under investigation, AT&T said initial findings suggest an internal technical failure during a network upgrade, rather than a cyberattack. Tens of thousands of customers were likely impacted before service was restored. The incident highlights society's increasing dependency on telecommunications infrastructure and wireless connectivity in the digital age.