Ibn Majah

Fiqh al-Hadith
“And Wahb bin Kaysan (the trustworthy Tabi‘i, rahimahullah) narrates that he heard Jabir bin Abdullah (radi Allahu anhu) saying: Whoever prays a rak‘ah in which he does not recite Surah al-Fatihah, his prayer is not valid, except behind the imam.”
↰ Malik narrated it in [موطا 1/ 84 ح 38] and its chain is authentic.
↰ Its chain is authentic.
From this athar, it is understood that, according to Sayyiduna Jabir (radi Allahu anhu), every rak‘ah in which Surah al-Fatihah is not recited is not valid. Contrary to this athar, Nīmwi Sahib says that if (the imam or the individual) does not recite anything in the last two rak‘ahs—meaning neither Surah al-Fatihah nor anything else, but rather stands silently—his prayer is still valid.
It is thus clear that the people of taqlid are opposed to this athar.
Secondly, in this athar as well, there is no prohibition of reciting al-Fatihah behind the imam.
Thirdly, recitation of al-Fatihah behind the imam is established from Sayyiduna Jabir (radi Allahu anhu). See: [سنن ابن ماجه 843 و سنده صحيح]
And fourthly, this athar is set aside because it is contrary to the majority of the Companions and to the marfu‘ ahadith.

Benefit:

➊ It is necessary to recite Surah Al-Fatihah even behind the imam.

➋ In silent (sirr) prayers, after reciting Surah Al-Fatihah behind the imam, another surah may also be recited.