Are all the Hadiths narrated by Al-Tirmidhi authentic? And is the Hadith that states that whoever recites Al-Dukhan on a given night will have seventy thousand angels seeking forgiveness for him among them? And how should one deal with Hadiths that are not narrated by the Two Shaykhs and whose authenticity is not mentioned?

Sunan al-Tirmidhi includes authentic (sahih) and good (hasan) hadiths, as well as many weak (da'if) hadiths, which Tirmidhi himself pointed out. Al-Albani dedicated a significant portion of his work to discussing their weakness. As for the hadith about reciting Surah Ad-Dukhan, its weakness has been previously established. Hadiths that are not attributed to the books of Sahih require consulting scholars to ascertain their authenticity, as Al-Suyuti mentioned in Alfiyyat al-Mushtalah regarding the methods of identifying authentic hadiths.