After changing an S3 bucket used for training data from SSE-S3 to SSE-KMS, SageMaker training jobs begin failing with AccessDenied errors. The engineer made no other configuration changes. What should the engineer do to fix the failures?

When an S3 bucket's encryption changes from SSE-S3 (S3-managed keys) to SSE-KMS (AWS Key Management Service), SageMaker training jobs require explicit permissions to interact with KMS. The AccessDenied errors indicate that the execution role used by the SageMaker jobs lacks these necessary KMS permissions. Adding kms:Encrypt and kms:Decrypt to the training job's execution role allows it to use the KMS key for data encryption and decryption during training. Incorrect options: s3:ListBucket and s3:GetObject are typically already present for S3 access; the issue is with KMS, not basic S3 operations. Setting aws:SecureTransport to True in the S3 bucket policy enforces HTTPS, which is unrelated to KMS key access. kms:CreateGrant is for creating grants on KMS keys, not for encrypting or decrypting data, and the user's policy doesn't affect the training job's execution role.