Unable to load package manifest

When installing my app, I see the following error in the log:

Code:

080A0410

Unit:

web.packagemanager.hooks

Description:

Trace message web.common.logger

myApp: Retrieving package manifest failed

Developer information:

source: packageAssets.go | hooks.(*PackageAssetsHook).OnInstall | 61

My package manifest file is attached (I needed to change the .json extension to .csv in order to upload the file). The relevant snapcraft.yaml section is below:

slots:
  package-assets:
    interface: content
    content: package-assets
    source:
        read:
          - $SNAP/package-assets/myApp

Is there any clue that error code can give me, or is there anything obvious that I am doing wrong? Thank you!

Pablo