Is this hadith authentic?
Narrated Aisha Zayd ibn Harithah came to Medina when Allah's Messenger (peace be upon him) was in my house. When he came to him and knocked at the door Allah's Messenger (peace be upon him) got up and went to him naked, trailing his garment. I swear by Allah that neither before nor after that did I ever see him naked. He then embraced him and kissed him. Tirmidhi transmitted it. (Tirmidhi Hadith, Number 1220-
Jami` at-Tirmidhi 2732
The hadith is da'īf (weak). The chain of narration of the hadith you are asking about is:
The problem in the narration chain lies in Ibrāhīm ibn Yahya ibn Mohammad ibn 'Abbād al-Madani, who is weak. At-Tirmidhi said that he had not seen anyone with a more blind heart than him (this is not a compliment), Abu al-Fat'h al-Azdi said his hadith was denounced (munkar, Arabic: منكر) especially through his father (Abu Yahya ibn Mohammad), Abu Hātim ar-Rāzi said he was weak in hadith, Ibn Hajar al-'Asqalāni said he was lenient in his hadith, and only 'Abdullah al-Hākim an-Naisapūri said he was trusted. Mohammad ibn Is'hāq is also a mudallis, i.e., he did not name where he got his hadiths from. Muhammad Nasiruddin al-Albani considered the hadith weak.
Worth noting that the phrase used in the Arabic language is (عريانا يجر ثوبه), which was translated to "naked, trailing his garment." The word (عريان) refers to someone who is (refer to E. W. Lane's Arabic-English Lexicon pp. 2030):
The phrase (يجر ثوبه) means dragging his garment, which means he was wearing his garment. It is quite common to use the word (عريان) not to indicate nakedness but to indicate taking off the top outer garment (الرداء) while one is wearing one's inner garments (الإزار والسراويل). You may refer to Sharh Mushkal al-Athār 4/415 for more information.
