After this add the below policy as it is in box.
Policy Name : S3CodeMediaDBBackupsFullAccess
Description : Full Access of mysqldbbackups buckets.
Policy Document :
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "s3:*",
"Resource": [
"arn:aws:s3:::mysqldbbackups-AWS_ACCOUNT_NAME",
"arn:aws:s3:::mysqldbbackups-AWS_ACCOUNT_NAME/*"
]
}
]
}