If the NAT gateway could not be created, specifies the error message for the failure, that corresponds to the error code.
For InsufficientFreeAddressesInSubnet: "Subnet has insufficient free addresses
to create this NAT gateway"
For Gateway.NotAttached: "Network vpc-xxxxxxxx has no Internet gateway
For InvalidAllocationID.NotFound: "Elastic IP address eipalloc-xxxxxxxx
could not be associated with this NAT gateway"
For Resource.AlreadyAssociated: "Elastic IP address eipalloc-xxxxxxxx
is already associated"
For InternalError: "Network interface eni-xxxxxxxx, created and used internally
by this NAT gateway is in an invalid state. Please try again."
For InvalidSubnetID.NotFound: "The specified subnet subnet-xxxxxxxx does
not exist or could not be found."