Abu Dawud said: According to the version of Ibn Mahdi, this tradition has been narrated by Ibn Fudail as a statement of Abu Hurairah and not as a saying of the Prophet (ﷺ)
In-book : Book 2, Hadith 540
English translation : Book 2, Hadith 929
2. Prayer (Kitab Al-Salat)
باب رَدِّ السَّلاَمِ فِي الصَّلاَةِ