What caused the 47-minute global outage of Google services?

Few days ago, a global outage knocked out major services of Google, including Gmail and YouTube

Google diagnosed the 47-minute global outage of its services including Gmail and YouTube as a mistake with its system for identifying users.

Google said it began moving tools that enable it to verify and track logged-in users to a new file storage system in October. In the process, it misreported portions of data causing an outage of services.

According to Republic, due to some technical reasons, some of the User ID from the previous system was left in a place and caused the outage in services for some users. Google said that the problem was identified at 03:48 within one minute of customer impact and at 04:08 engineers identified the root cause.

The company said that the error rates were returned to normal levels at 04:33 and almost all services were restored. However, some user services took longer to recover.