Facebook and its owned platforms were down for almost six hours on October 4, which affected not only billions of users around the world but also game companies using its services.

“Our engineering teams have learned that configuration changes on the backbone routers that coordinate network traffic between our data centers caused issues that interrupted this communication,” Facebook explained in a statement. “This disruption to network traffic had a cascading effect on the way our data centers communicate, bringing our services to a halt.”

As a result, people around the world had trouble accessing Facebook and platforms like Instagram and WhatsApp. The outage also affected Oculus, which requires its users to have a Facebook account.

According to GamesIndustry.biz, the halt also made it difficult for users to log in to different mobile games using their Facebook accounts. The list of titles includes Pokémon GO and FIFA Mobile.

Facebook later apologized for the impact of this outage, saying that the company is now “working to understand more about what happened today so we can continue to make our infrastructure more resilient.”