The Cellcom cyberattack is the alleged cause of service outages

Cellcom, a mobile carrier based in Wisconsin, has confirmed that a cyberattack caused the extensive service outage that began on the evening of May 14, 2025.

This disruption impacted voice and SMS services for users throughout Wisconsin and Upper Michigan, preventing many customers from making calls or sending texts.

Initially labelling the incident as a technical problem, Cellcom officially recognised the cyberattack several days later. Moreover, its CEO addressed the issue in a statement.

The CEO explained that Cellcom had experienced a “cyber incident,” which, although unfortunate, did not surprise the company.

In addition, it also highlighted that Cellcom had established protocols and response plans for such events and adhered to these procedures from the outset.

This process involved engaging external service providers, notifying the FBI and state officials, and working diligently to restore systems securely.

The CEO also emphasised that the attack focused on a part of the company’s network, distinct from where sensitive customer data was held. The company also reassured customers that there was no evidence suggesting that personal information, such as names, addresses, or financial details, had been compromised during the breach.

 

Cellcom initially claimed that the outages were only due to technical difficulties.

 

During the initial phase of the disruption, Cellcom insisted that the outage resulted from technical difficulties, claiming that data services, iMessage, RCS messaging, and 911 emergency services remained operational.

However, customer frustration increased as the inability to access essential mobile services and port numbers to other carriers continued.

By May 19, Cellcom had started to restore limited services, including SMS messaging and the ability to make and receive calls among Cellcom subscribers.

The company has indicated that while it cannot provide a specific timeline for complete service restoration, it aims to finish by the end of the week.

In a service update on the company’s website, Cellcom mentioned that although they could not guarantee exact milestones, progress was being made, and full restoration was anticipated “by or before the end of this week.”

For subscribers facing service problems, the company has advised them to toggle airplane mode on and off or restart their devices to help re-establish connectivity.