Twitter user Tzatl tweeted at the company on Sunday, asking: "Did you guys really forget to renew a certificate?" Microsoft responded that it had isolated the problem and was applying a fix, referring users to entry EX257883 under its service health dashboard. The issue provoked some teasing from users on Twitter. "Someone done goofed," replied one user, along with a picture of the untrusted certificate report from Digicert Cloud Services. This isn't the first time a large technology company has downed a service by forgetting to renew a certificate. Last month, Epic Games accidentally allowed a certificate used across many of its internal-facing services to expire. That took account logins offline for many of its most popular games, including Fortnite.