After many Americans woke up Thursday without cellphone service, AT&T said it has restored service to customers.
In a statement released by AT&T late Thursday morning, the company said three-quarters of its customers have had cellphone service restored.
"Some of our customers are experiencing wireless service interruptions this morning. Our network teams took immediate action and so far three-quarters of our network has been restored. We are working as quickly as possible to restore service to remaining customers," a company spokesperson said.
The Federal Communications Commission said its Public Safety and Homeland Security Bureau is investigating what caused the massive outage.
"We are aware of the reported wireless outages, and our Public Safety and Homeland Security Bureau is actively investigating. We are in touch with AT&T and public safety authorities, including FirstNet, as well as other providers," the FCC said.
The FBI was also in touch with AT&T, it said.
"Should we learn of any malicious activity we will respond accordingly," the FBI said of the incident.
Thousands of AT&T customers across the country began reporting outages on the website Down Detector before 4 a.m. ET. The outage continued for multiple hours into the morning. The outage meant that phones were left in SOS mode, which only allows emergency calls.
There was a peak of some 73,000 reports of interrupted service early in the day, but by Thursday afternoon, Down Detector showed that outages had declined significantly.
AT&T has not said what caused the outage. In a statement, AT&T did have a suggestion for those without service.
"We encourage the use of Wi-Fi calling until service is restored," AT&T said.
Numerous police departments said callers were struggling to reach 911 services. Those departments also recommended making calls in Wi-Fi mode.
Users of several other cellphone services, such as Cricket Wireless, Verizon and T-Mobile, also reported sporadic outages on Down Detector. Those outages do not appear to be as widespread as AT&T's outage. Verizon said early Thursday that its network was operating normally and customers only experienced problems "when calling or texting with customers served by another carrier."
According to 2023 Statista data, AT&T is the nation's largest cellphone provider with 46% share of the industry. It serves more than 240 million subscribers.
SEE MORE: What is 5G internet?
To enable Wi-Fi calling on an iPhone,go to Settings, tap Phone, and then tap Wi-Fi Calling.
To utilize Wi-Fi calling on an Android phone, open the Phone app, tap More Settings, tap Calls, and tap Wi-Fi Calling.
You will need to be connected to a wireless network in order for this feature to work.
While the outage has led to a lot of speculation over what caused it, the Space Weather Prediction Center said last night's solar flares were likely not the culprit.
"The Sun emitted two strong solar flares (both R3 on the NOAA Space Weather Scales), the first one peaking at 6:07 p.m. EST on Feb. 21, 2024, and the second peaking at 1:32 a.m. EST on Feb. 22, 2024," the agency said in a statement to Scripps News. "While solar flares can affect communication systems, radar, and the Global Positioning System, based on the intensity of the eruption and associated phenomena, it is highly unlikely that these flares contributed to the widely reported cellular network outages. "
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