My paternal uncles from the Ansar, who were companions of the Messenger of Allah ﷺ, told me, "The crescent moon of Shawwal was obscured from us, so we began the day fasting. Then a group of riders arrived at the end of the day and testified before the Prophet ﷺ that they had sighted the crescent the previous day. The Messenger of Allah ﷺ ordered them to break their fast and to go out the next morning for their Eid prayer."
حدثنا أبو بكر بن أبي شيبة حدثنا هشيم عن أبي بشر
حدثني عمومتي من الأنصار من أصحاب رسول الله ﷺ قالوا أغمي علينا هلال شوال فأصبحنا صياما فجاء ركب من آخر النهار فشهدوا عند النبي ﷺ أنهم رأوا الهلال بالأمس فأمرهم رسول الله ﷺ أن يفطروا وأن يخرجوا إلى عيدهم من الغد
[Its chain is sahih] Abu Dawud narrated it in the Book of Prayer, Chapter "If the Imam Does Not Go Out for the Eid on Its Day, He Goes Out the Next Day," hadith no. 1157, from the hadith of Abu Bishr Jafar, through him, and Ibn Hibban, Bayhaqi, Ibn Hazm and others graded it sahih.