Jami` at-Tirmidhi 2779
جامع الترمذي#2779SahihNarrated Dhakwan:from the freed slave of 'Amr bin Al-'As that 'Amr bin Al-'As sent him to 'Ali seeking his permission to enter upon Asma bint Umais, so he permitted him. When he was finished from what he needed, the freed slave of 'Amr bin Al-'As asked about that, so he said: "Indeed the Prophet (ﷺ) prohibited us - or - prohibited that we enter upon women, without the permission of their husbands
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Bashar Awad MaaroufHasan
Zubair Ali ZaiHasan
In-book reference: 43:49