While AT&T customers nationwide struggled Thursday to make calls or check their emails on the go, Jennifer Lundy had a different problem — she couldn’t get into her bank account.

Due to the cellular carrier’s widespread outage, Lundy, who lives in Valdosta, wasn’t able to receive text messages from her bank to get access to her accounts through two-factor authentication, causing her to worry she could miss important payments.

“We tried to pay off credit card debt that was due and could not log in to do that. (It’s) a hindrance,” Lundy said in an email to The Atlanta-Journal Constitution. She wasn’t able to get a phone call to connect for an interview.

An hours-long and massive AT&T outage, which federal authorities said Thursday was under investigation, upended 911 service in some communities and thrust customers into the dark ages without the ability to call, check emails, use navigation apps or dozens of other mobile tasks that make up modern life. The outage hit major cities, including Atlanta, Chicago, New York and San Francisco.

Emergency services, utilities, schools and governments urged residents to make critical calls via landlines. Other alternatives included having to find a phone that used another carrier or online portals, which also required internet access.

The confusion thrust everyday people into the role of product tester, which Doraville Councilman Andy Yeoman detailed on Facebook.

“I’ve restarted three times. I’ve tapped it. I’ve toggled the cellular network in airplane mode on and off at least 30 times,” he wrote, adding that the frustration led him to just toss his phone off the bed, which also didn’t work.

Other carriers’ users reported some problems, but it appeared to be with contacting AT&T customers, both Verizon and T-Mobile representatives confirmed. Smaller providers using AT&T’s network, such as Cricket Wireless, were also affected. FirstNet, the wireless broadband network for first responders that is operated by AT&T, was unaffected.

It took hours of complaints by customers before Dallas, Texas-based AT&T, the country’s largest carrier with more than 240 million subscribers, acknowledged the widespread network outages, which quickly became a trending topic on social media. Users began reporting loss of service shortly before 4 a.m., DownDetector shows. The website tracks outages by user-submitted reports, which peaked at about 74,000 customer-reported outages, though is likely a significant undercount of affected customers.

Ken Bernhardt, a Georgia State University marketing professor emeritus, said it’s important for companies to keep their customers informed when issues arise.

“Silence can cause the most damage of all,” he said.

AT&T said it restored wireless service to all affected customer by 3:10 p.m. Eastern time, but the company did not immediately share what caused the service disruption.

“Keeping our customers connected remains our top priority, and we are taking steps to ensure our customers do not experience this again in the future,” the company said.

Dealing with an ‘SOS’

The ability to call anyone from pretty much anywhere has become an expectation.

Many AT&T customers woke up Thursday to see an “SOS” message displayed in the status bar on their iPhones, a signal their device is having trouble connecting to a cellular network but can still make emergency calls. Some took to social media to search for answers. Others called 911 to see if emergency lines still worked, to the frustration of law enforcement agencies.

“Please do not do this,” Massachusetts State Police posted on X, formerly known as Twitter, after receiving a flood of 911 calls where the emergency was merely curiosity.

Atlanta officials said emergency lines were unaffected Thursday, but the outage knocked out the city’s non-emergency 911 line (404-658-6666) and 311 line, which is typically used for reporting issues like potholes or a missed trash pickup. Both were offline for hours, with the city advising residents to either send a text message or use the city’s E-911 web portal at www.atlantaga.gov/request-dispatch.

The outage comes on the heels of Atlanta’s 911 system experiencing “technical difficulties” that briefly blocked incoming calls Tuesday afternoon. Officials said that issue was caused by problems with AT&T’s network and impacted cities across the Southeast.

Other metro Atlanta counties, including Cobb and Gwinnett, said they didn’t experience 911 outages. Students at some universities that use services that rely on cellular data, such as multi-factor authentication security measures, were also affected. Several Fortune 500 companies based in metro Atlanta said their operations were minimally impacted.

The FBI and U.S. Department of Homeland Security’s Cybersecurity and Infrastructure Security Agency confirmed investigations into the outage and whether it was a cyberattack of some kind. The Federal Communications Commission is also probing the incident.

Prior outages have led to costly settlements with cellular networks. T-Mobile agreed to pay $19.5 million following a 2020 outage that led to more than 20,000 failed 911 calls.

Lee McKnight, an associate professor in the iSchool at Syracuse University, told the Associated Press that a cyberattack seemed unlikely and that human error or a cloud misconfiguration was most likely to blame.

Bernhardt, the Georgia State professor, said it’s vital large companies have crisis communications plans in place for worst-case scenarios, adding that earnest and prompt communication often leads to fewer burned bridges with customers.

“Consumers, if handled right, are very forgiving in situations like this,” he said.

— AJC reporters Michael E. Kanell, Vanessa McCray, Taylor Croft and Jillian Price contributed to this article.