It was narrated from 'Abdullah bin Ja'far that:The Messenger of Allah (ﷺ) said: "Whoever has doubt during his prayer, let him prostrate twice." (One of the narrators) Hajjaj said: "After he has said the taslim." (Another of them) Rawh said: "While he is sitting
Hadith No. 1251
Sunan an Nasai
Gradings:
Abu Ghuddah:
Daif
Al-Albani:
Daif
Zubair Ali Zai:
Hasan