When the Prophet ﷺ entered the privy, he removed his ring. Abu Dawud said: This is a munkar tradition, i.e. it contradicts the well-known version reported by reliable narrators. On the authority of Anas the well-known version says: The Prophet ﷺ had a silver ring made for him. Then he cast it off. The misunderstanding is on the part of Hammam (who is the narrator of the previous tradition mentioned in the text). This is transmitted only by Hammam.  

كَانَ النَّبِيُّ ﷺ إِذَا دَخَلَ الْخَلاَءَ وَضَعَ خَاتَمَهُ