We were behind the Messenger of Allah (ﷺ) at the dawn prayer, and he recited (the passage), but the recitation became difficult for him. Then when he finished, he said: Perhaps you recite behind your imam? We replied: Yes, it is so, Messenger of Allah. He said: Do not do so except when it is Fatihat al-Kitab, for he who does not recite it is not credited with having prayed.
Sunan Abi Dawud Book 2, Hadith 433
← Previous Hadith the prayer is not valid I one does not recite fatihat al-kitab and something more, sufyan( the narrator) said: This applies to a man who prays alone.

Sunan Abi Dawud Book 2, Hadith 432 Next Hadith → “Ubadah b. al-samit came to late to lead the morning prayer. Abu Nu’aim, the mu’adhdhin, pronounced the takbir and he led the people in prayer. Then Ubadah came and I was with him. We Joined the row behind Abu Nu’aim, while Abu Nu’aim was reciting the Quran loudly. Then ‘Ubadah began to recite the Umm al-Quran (I.e Surah al Fatihah). When he finished, I said to Ubadah: I heard you reciting the Umm al-Quran while Abu Nu’aim was reciting Quran loudly. He replied: yes> The Messenger of Allah (ﷺ) led us in a certain prayer in which the Quran is recited loudly, but he became confused in the recitation. When he finished he turned his face to us and said: Do you recite when I recite the Quran loudly? Some of us said: we do so; this is why I said to myself: What is that which confused me (in the recitation of ) the Quran. Do not recite anything from the Quran when I recite it loudly except the Umm al-Quran.

Sunan Abi Dawud Book 2, Hadith 434