A man prayed alone behind the rows, so the Prophet ﷺ ordered him to repeat the prayer.
حدثنا وكيع قال حدثني يزيد بن زياد بن أبي الجعد عن عمه عبيد بن أبي الجعد عن زياد بن أبي الجعد
أن رجلا صلى خلف الصفوف وحده فأمره النبي ﷺ أن يعيد
Its isnad is sahih. Yazid bin Ziyad bin Abu Jaad Kufi Ashjai is deemed trustworthy. Bukhari narrated from him in Afal al-Ibad, and he has narrations in the Sunan. Ubayd bin Abu Jaad Ashjai, also said to be Ghatafani, is likewise deemed trustworthy, and he has a narration with Nasai. The hadith has already appeared at 17923.