AT&T said calls between users were not affected.
AT&T on Tuesday resolved a “carrier interoperability issue” that customers were experiencing, the company said in a statement.
AT&T said at the time that customers had begun reporting “nationwide issues affecting their ability to make calls to non-AT&T users.”
The company later clarified that its network “did not experience a nationwide outage,” but some users across the country were affected.
“The carrier is working as quickly as possible to diagnose and resolve the issue,” AT&T said.
The company later said it mistakenly sent a “radio impact notification” to its 911 call center during the outage.
“911 services nationwide are operating normally at this time and there is no impact to our customers,” AT&T said in a statement around 5:20 p.m. ET.
In a post on X, the Federal Communications Commission said it was “aware of reports of consumers in multiple states experiencing wireless connectivity issues and is currently investigating.”
Verizon said its network is functioning normally, but that some users, primarily in the Northeast and Midwest, are “experiencing issues making calls and texting to customers of other carriers.”
This is the second time in the last three months that AT&T has experienced an outage.
AT&T customers across the US experienced similar outages after a software update in late February, the company said.
A power outage in February temporarily affected 911 services in several states.
The FCC has launched an investigation into the incident.
ABC News’ Elizabeth Schultz contributed to this report.
