Nafi' bin Mahmud al-Ansari narrates from Sayyiduna Ubadah (may Allah be pleased with him): Ubadah (may Allah be pleased with him) was in Iliya. He was late for the morning prayer, so Abu Nu'aym established the prayer; he is the one who was the first to give the adhan in Bayt al-Maqdis. I came with Sayyiduna Ubadah (may Allah be pleased with him), and he came and joined the row with the people. Abu Nu'aym was reciting aloud, and Ubadah (may Allah be pleased with him) was reciting Surah al-Fatihah (quietly), and I could make it out. When he finished the prayer, I said: I heard you reciting Surah al-Fatihah? He said: Yes. The Messenger of Allah (peace and blessings be upon him) led us in a prayer with loud recitation and said: "When I am reciting aloud, do not recite anything except Surah al-Fatihah."
The hadith is sahih (authentic) from Ubadah bin al-Samit from the Prophet (peace and blessings be upon him), and it has supporting reports (shawahid).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2921