T-Mobile U.S. has agreed to settle a $19.5 million probe into a major outage in 2020 that led to more than 23,000 failed 911 calls.

As part of its consent decree with the Federal Communications Commission, T-Mobile has also committed to improving outage notifications in the future.

An FCC report from October 2020 found that the outage of T-Mobile nationwide disrupted telephone and SMS services and access to data services in many areas of the U.S., resulting in the outage of at least 250 million calls and at least 41% of all calls trying to use the T-Mobile network during the outage were unable to connect.

Then-FCC chairman Ajit Pai said the FCC report showed the wireless carrier had violated best practices in network reliability that could potentially have prevented the 2020 outage.

In addition, the FCC report said the outage was due to a device failure that was exacerbated by a network routing misconfiguration that happened when T-Mobile installed a new router on its network.

The mobile operator had previously stated that its network suffered an 18% reduction in calls made during the outage and admitted that subscribers had to make 2-3 attempts during the outage before the call was successfully connected.