A banking company recently launched an Amazon RDS for MySQL DB instance as part of a proof-of-concept project. A database specialist has configured automated database snapshots. As a part of routine testing, the database specialist noticed one day that the automated database snapshot was not created.
Which of the following are possible reasons why the snapshot was not created? (Choose two.)

A. A copy of the RDS automated snapshot for this DB instance is in progress within the same AWS Region. B. A copy of the RDS automated snapshot for this DB instance is in progress in a different AWS Region. C. The RDS maintenance window is not configured. D. The RDS DB instance is in the STORAGE_FULL state. E. RDS event notifications have not been enabled.