"No explicit selection and an implicit one could not be determined" error for my JPA request

Question

I have three SQL tables

1. The "Accedant" table that has an idAccedant
2. The "Emetteur" table that has an idEmetteur and a foreign key towards the Accedant table
3. The "Asso_Etab_Emet" table which is an assocation table between a table called "Etablissement" and the "Emetteur" table. So the "Asso_Etab_Emet" table has two foreign keys, one towards the Etablissement table and one toward the Emetteur table

I want to build a

Specification<Etablissement>

with the idAccedant as input data, to get, at the end, the list of all the Etablissement linked to an Emetteur :

Page<Etablissement> etablissementsPage = etablissementDao.findAll(specEtab, configPage);

My code that aims at building the Specification is the following

@Override
public Specification<Etablissement> findActifByExploitantSpec(Long idAccedant) {
return ((root, query, builder) -> {

    Subquery<Emetteur> emetteurSubquery = query.subquery(Emetteur.class);
    Root<Emetteur> emetteurRoot = emetteurSubquery.from(Emetteur.class);

    emetteurSubquery 
       = emetteurSubquery.where(builder.equal(emetteurRoot.get(Emetteur_.accedant).get(Accedant_.id), idAccedant));
    
    Subquery<Etablissement> etablissementSubquery = query.subquery(Etablissement.class);
    Root<Etablissement> etablissementRoot = etablissementSubquery.from(Etablissement.class);
    
    Root<EtablissementEmetteur> etablissementEmetteurRoot = etablissementSubquery.from(EtablissementEmetteur.class);
    etablissementSubquery 
        = etablissementSubquery.select(etablissementEmetteurRoot.get(EtablissementEmetteur_.etablissement));

    etablissementSubquery = etablissementSubquery.where(
            builder.in(etablissementEmetteurRoot.get(EtablissementEmetteur_.emetteur)).value(emetteurSubquery));

    return builder.in(root).value(etablissementSubquery);
});
}

I have a "No explicit selection and an implicit one could not be determined" error when testing via my Angular webapp