What just happened? Over 60 million phones in 11 countries lost their network coverage for up to 24 hours on Thursday, and it turns out the entire problem was an expired certificate. Certificates are software keys that enable certain functionality, but they can require occasional updates so that they don’t expire, something Swedish owned telecommunication equipment manufacturer Ericsson didn’t do.

Ericsson has their fingers in a lot of pies, but the largest portion of their business is constructing the mobile networks big brands such as the UK’s O2 and the Japanese Softbank use. Unfortunately for those network’s customers, the security certificate on their devices expired on Thursday morning. Softbank’s 30 million subscribers received a fix after 4-5 hours, but O2’s 32 million customers had to wait until early Friday morning.

The full extent of the network shut down hasn’t quite been determined yet, as Ericsson hasn’t provided the names of the affected countries, just the number. Despite certain rumors regarding AT&T and Verizon network issues at the same time, Ericsson says that the United States was unaffected by the expired certificate.

Amusingly, when the Financial Times first reported the issue and pointed the finger at Ericsson, they claimed they were unaware of any issues relating to their networking equipment or software. Ericsson’s CEO and President Börje Ekholmhas has since apologized for the network failure.

“The faulty software that has caused these issues is being decommissioned and we apologize not only to our customers but also to their customers. We work hard to ensure that our customers can limit the impact and restore their services as soon as possible.”

With Ericsson working with companies to provide 5G in many countries that include Sweden, Denmark, Norway, Italy, South Africa, India, Japan, Australia and lots more, let’s hope they learn from this mistake before equipping self-driving trucks to their 5G networks.