Vault doesn't recognize storage backend

[zezhuq]

using amd64 image of docker vault

I'm running
docker run --rm --name vault -p 8200:8200 --volume /etc/vault/config.hcl -e VAULT_ADDR=http://localhost:8200 -it amd64/vault server -config=/etc/vault/config.hcl

but I'm getting an error:
A storage backend must be specified

but my config.hcl file has a storage backend specified:
storage "dynamodb" {
advertise_addr = "IP-ADDRESS-OF-MACHINE"
region = "REGION"
table = "NAME-OF-TABLE"
read_capacity = "5"
write_capacity = "5"
ha_enabled = "true"
}

context: I'm also running this on EC2 instance, and I'm not sure if vault is automatically pulling credentials to be able to use dynamodb