When you get the following error:
Cannot add the instance salesforce.{type}.instance.{name} because the {name} type is not managed by Salto in the target environment.
The most common reasons are:
Type was recently created in the target org: fetch the target (a partial fetch of the type is enough, e.g. CustomObject for Custom Metadata Types), then refresh comparison on the deployment.
Type doesn't exist in the target org: add the type itself to the deployment.
Type is excluded in the target's configuration: include it (see Supported Salesforce Types), then fetch and refresh the deployment.
