Cannot get Sailfish contacts with QContactManager

Question

I try to get Jolla's (SailfishOS) phonebook contacts from QContactManager.

QContactManager *manager = new QContactManager();
QList<QContact> results = manager->contacts();

results list contains 0 contact.
I check also if there is error:

QContactManager::Error error;

QContactManager's error code is NoError.
Then I check available managers.

manager->availableManagers()

• org.nemomobile.contacts.sqlite
• invalid

• memory

  QContactManager *manager = new QContactManager();

  QContactManager *manager = new

  QContactManager("org.nemomobile.contacts.sqlite");

In both case: manager no error, but manager->managerName() result is invalid.

On the other hand, if I create manager as:

QContactManager *manager = new QContactManager("memory");

... I can use this memory based QContactManager (for example save and get contacts) normally.