Is "Whoever has not prayed Witr is not one of us" a sound hadith from the Messenger of Allah, may Allah bless him and grant him peace?

The hadith: "He who does not pray Witr is not one of us" was narrated by Ahmad, Al-Hakim, and others. Another narration by them states: "Witr is a right, so he who does not pray Witr is not one of us." Al-Hafiz said about it in Bulugh al-Maram: "Abu Dawud narrated it with a weak chain, and Al-Hakim authenticated it." Al-Arna'ut declared it hasan (good), while Al-Albani declared it da'if (weak). The correct view is that it is hasan li ghayrihi (good due to external corroboration).