Unable to register an existing component (Template) using the UI in Backstage

Here is the scaffolder section in my app-config.yaml file which doesn't contain any item under location :

scaffolder:
 catalog:
   import:
     entityFilename: catalog-info.yaml
     pullRequestBranchName: backstage-integration
   rules:
     - allow: [Component, System, API, Resource, Domain, Template]
   locations:

When I choose to add this template from the UI (Register an existing component) I get this error :

{
   "error":{
      "name":"InputError",
      "message":"NotAllowedError: Entity template:default/springboot-template at url:https://github.com/backstage/software-templates/blob/main/scaffolder-templates/springboot-grpc-template/template.yaml, originated at url:https://github.com/backstage/software-templates/blob/main/scaffolder-templates/springboot-grpc-template/template.yaml, is not of an allowed kind for that location"
   },
   "request":{
      "method":"POST",
      "url":"/locations?dryRun=true"
   },
   "response":{
      "statusCode":400
   }
}

The issue was that my app-config.yaml files was not correctly formatted:

I had :

scaffolder:
    catalog:
       ....

Instead of :

scaffolder:
    ...
catalog:
    ....