Search for projects whose related organization id equals to a value

I’m trying to search for projects whose relation organization matches to an id. My resultCount is 0. This doesn’t match my expectation. Is something wrong with my query? What has to be improved? Thanks in advance

Request URL: https://api.{{HOST}}/v2/projects/search?include=organization
Request BODY:

{

    "query": {

        "_rel": {

            "organizations": { "id": {

                "_eq": "fffd8868-c558-11ec-9e57-73f4ef662f2b"

            }}

        }

        

    },

    "limit": 1000,

    "inlineData": true

}

Ok the solution is the following:

{
    "query": {
        "_rel": {
            "organizations": { "organization.id": {
                "_eq": "fffd8868-c558-11ec-9e57-73f4ef662f2b"
            }}
        }
        
    },
    "limit": 1000,
    "inlineData": true
}