Unable to use existing asset store

I’m trying to use a folder for asset storage where the folder has existing assets. This is actually a mounted folder but all the files are available to the application.
However when I start squidex I can’t find any of the files in the assets folder.

I have tried using rebuild assets and rebuild index in the configuration but this does not help.

Is it possible to access assets this way or do I have to think of some other way?

The metadata of the assets are hosted in MongoDB and used for querying. So you need to upload your files.