Must the prayers that were performed without washing the forearms during ablution be re-offered due to ignorance of its obligation?

Washing the forearms up to the elbows is an obligatory act of ablution (wudu') according to the Qur'an, Sunnah, and scholarly consensus (Ijma'). Whoever neglects washing the forearms during ablution must repeat the prayer, unless they were ignorant of the ruling, in which case their ignorance is excused, and they are not required to repeat it. As for rinsing the mouth (madmadah) and sniffing water into the nose (istinshaq), there is a difference of opinion among scholars regarding their obligation. The majority of scholars hold that they are not obligatory. Therefore, whoever is given a fatwa that they are not obligatory incurs no blame and is not commanded to make up the prayers performed without rinsing the mouth or sniffing water into the nose.