Jami` at-Tirmidhi 486
جامع الترمذي#486Da'ifUmar bin Al-Khattab narrated:"Indeed the supplication stops between the heavens and the earth. Nothing of it is raised up until you send Salat upon your Prophet
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirHasan
Al-AlbaniHasan
Zubair Ali ZaiDaif
In-book reference: 3:34