Has it been reported in the books of Ahlus-Sunnah wal-Jama'ah that Amir al-Mu'minin, Umar ibn al-Khattab, may Allah be pleased with him, drank alcohol after his conversion to Islam?

The accusation that Umar ibn al-Khattab, may Allah be pleased with him, drank alcohol is a lie and a fabrication. Al-Faruq declared war on alcohol since his acceptance of Islam and was keen on its prohibition, as is evident from his repeated requests to Allah for a clear statement regarding alcohol, the revelation of the Quranic verses concerning it, and then his determination of the punishment for drinking it. What Umar drank in the story of his death was non-intoxicating nabidh, which the Prophet, may Allah's prayers and peace be upon him, used to drink. It is water sweetened with raisins or similar ingredients, not the forbidden intoxicant.