Can’t recall part of a verse during prayer
Question

                What happens if an Imam forgets the 
ending of the verse during prayer and no 
one reminds him?
Praise be to Allah.If the Imam recited a part of the Qur’an and forgot the ending of the 
verse, and none of the followers reminded him of it, he can choose 
either to say the takbeer and discontinue the recitation, or recite a 
verse or more from another surah. But this is allowed only if the 
forgotten part is not from Al-Fatihah. As far as Al-Fatihah is 
concerned, it must be recited in its entirety as reciting it is an 
obligatory act of prayer.1