What is the ruling regarding past prayers in which the palm was not washed during wudu due to forgetfulness?

Washing the hands at the beginning of wudu' is a Sunnah that does not suffice for the obligatory washing of the hands according to the jurists. Whoever doubts the validity of his wudu' after completing an act of worship, his doubt is not considered. However, if there is certainty or strong presumption that he washed them with the intention of the Sunnah, then the wudu' is valid according to the Hanafis, and there is no need to make up past prayers. As for other than the Hanafis, the wudu' is invalid, and it is obligatory to make up past prayers, even if it was due to ignorance. Sheikh al-Islam Ibn Taymiyyah held the view that whoever omitted this out of ignorance is not obligated to repeat past prayers, but only to repeat the prayer of the current time.