Many Xbox users were unable to play games on their consoles for a large chunk of Monday. After engineers resolved the problem, an executive from the division offered some clarity as to what went wrong.

Scott Van Vliet, Xbox's chief technology officer, said an external licensing service that Xbox and several of its store and publishing partners rely on started to go on the fritz late Sunday night. "This caused some sign-in scenarios to fail, and it caused many scenarios that require an entitlement check to also fail, such as listing out your Full Library and launching games that you own," Van Vliet wrote on X.

Xbox's on-call teams detected the issue during the night. "Once we isolated the failing infrastructure, we shifted traffic onto the healthy parts of the system while the team continued to work towards a root cause," Van Vliet wrote. Engineers gradually restored services across various regions. Everything was back online as of 5:30PM ET on Monday.

Van Vliet (who became CTO in May) said Xbox was carrying out a review of what he described as an "unacceptable situation" after a single point of failure disrupted services for many consumers. He noted that the next steps involve "hardening the dependencies underneath sign in and game launch, improving how we detect and contain this class of failure and being faster and clearer with you when something breaks."

The outage meant that some players were unable to play digital and/or disc-based games. It also affected sign-ins, launching apps and finding games on Xbox's digital storefront. It impacted Xbox Series X/S, Xbox One and Xbox 360, as well as backward compatibility features.

"Over the coming weeks, you'll hear more from me about our services, our platform and the work we're doing to make Xbox better," Van Vliet noted. As part of a restructuring of the division, Xbox laid off 1,600 workers this month and said it would cut the same number of jobs by the end of next June.