Vault , Android

I have a content model, named test with field test. Then I want to get this model via vault. I have a space and do requstSync - got SyncResult isSuccessful - true. After that I trying to do vault.observe(Test.class).all(). subscribe (onNext, onComplete, onSubscribe, onError ). For me I got only two callbacks onSubscribe and onError. Could you please help. me, why I don’t get any data to onNext? I have tried content type as contentId and juts ‘test’.