Sunan Ibn Majah 696
سنن ابن ماجه#696SahihIt was narrated that Anas bin Malik said:"The Messenger of Allah said: 'Whoever forgets a prayer, let him perform it when he remembers it
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Zubair Ali ZaiSahih
In-book reference: 2:30