A widespread AT&T outage affected more than 70,000 customers as of 8 a.m. ET, according to Most of these problems were concentrated in Houston, Chicago, Dallas, Los Angeles and Atlanta. It affected cell service and data connections, with many customers noting they couldn’t even reach 911.

It is not yet clear what caused the service outage, as it is ongoing. AT&T issued a saying it’s “working urgently to restore service.” The company is encouraging customers to use Wi-Fi calling until the issue is resolved.

Thousands of Verizon and T-Mobile customers also reported outages, but both companies said those affected were trying to reach AT&T numbers. The market called this a serious problem, as AT&T shares fell nearly three percent since opening trading this morning.

Cellular network outages are a regular part of life, but the fact that many affected customers are unable to contact 911 and other emergency services is particularly troubling. The San Francisco Fire Department urged residents to try calling 911 from a landline or “contact a friend or family member” who has signed up for another carrier.

Atlanta Mayor Andre Dickens could make and receive 911 calls, but many AT&T customers could not. Dickens suggested that city residents contact AT&T for service inquiries rather than Atlanta’s emergency services system. The Massachusetts State Police echoed that sentiment, noting that customers have been flooding its 911 center with inquiries about cell service. “Please don’t do this,”

This is an ongoing issue, and we’ll update this story when service is restored or when AT&T issues an update on the cause.

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