He had slaughtered his sacrifice before the Messenger of Allah ﷺ went out to pray. When the Messenger of Allah ﷺ had finished the prayer, he mentioned this to him, and he ordered him to repeat his sacrifice.
حدثنا يزيد قال أخبرنا يحيى بن سعيد عن عباد بن تميم أخبره
أنه ذبح قبل أن يغدو رسول الله ﷺ فلما صلى رسول الله ﷺ ذكر ذلك له فأمره أن يعيد أضحيته