Only the root level outputs from the remote state are accessible. Outputs from modules within the state cannot be accessed. If you want a module output to be accessible via a remote state, you must thread the output through to a root output.
An example is shown below:
```
module "app" {
source = "..."
}
output "app_value" {
value = "${module.app.value}"
}
```
In this example, the output `value` from the "app" module is available as "app_value". If this root level output hadn't been created, then a remote state resource wouldn't be able to access the `value` output on the module.