Sunan Abi Dawud 1445
سنن أبي داود#1445SahihAnas b. Malik said:The Prophet (ﷺ) recited the supplication for a month (in prayer) and then gave it up
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih Muslim (677)
In-book reference: 8:30