"Unknown cipher type" on conditioned json import for organization

We are trying to import our existing data from PasswortDepot. This software is not supported by Bitwarden import, so we made a conditioned json from it’s export.
When trying to import this json file into Bitwarden, we get an “Unknown cipher type” message without any futher details.

We followed these instructions:

The json is structured like this:

{
    "collections": [
        {
            "id": "...",
            "organizationId": "...",
            "name": "..."
        },
		...
    ],
    "items": [
        {
            "organizationId": "...",
            "collectionIds": [
                "..."
            ],
            "name": "...",
            "type": "1",
            "login": {
                "password": "...",
                "username": "..."
            }
        },
		...
    ]
}

Any idea why this is failing on import?

Thank you very much!