On Monday at 3:46 pm UTC, several services on GitHub.com experienced a 41-minute disruption, and as a result, some services were degraded for a longer period. Our initial investigation suggests a logic error introduced into our deployment pipeline manifested during a subsequent and unrelated deployment of the GitHub.com website. This chain of events destabilized a number of internal systems, complicated our recovery efforts, and resulted in an interruption of service.
All GitHub services are back to normal and no data was lost. We take reliability very seriously and sincerely apologize for this disruption. Millions of people and businesses depend on GitHub, and we know that our community feels the effects of our availability issues acutely.
We are currently conducting a thorough investigation into the contributing factors to this event and will share the findings of our analysis with the community. From this incident, we hope to learn new ways to maintain your trust.
Source: GitHub Old