The response to them is that this hadith is weak, for its transmission revolves around Muhammad ibn Khālid al-Jundī.

Al-Dhahabī said of him: “Al-Azdī said: ‘He narrates rejected hadiths.’ Abū Abd Allah al-Hākim said: ‘He is unknown.’ I say—the speaker here is al-Dhahabī—his hadith, ‘There is no Mahdi except Jesus son of Mary,’ is a rejected report transmitted by Ibn Mājah.” (1)

Shaykh al-Islam Ibn Taymiyya said: “This hadith is weak. Abū Muhammad ibn al-Walīd al-Baghdādī and others relied upon it, but it is not something that may be relied upon. Ibn Mājah narrated it from Yūnus, from al-Shāfiī. Al-Shāfiī narrated it from a Yemeni man named Muhammad ibn Khālid al-Jundī, whose reports may not be cited as proof. It is not found in al-Shāfiī’s Musnad. It has also been said that al-Shāfiī did not hear it from al-Jundī and that Yūnus did not hear it from al-Shāfiī.” (2)

The hadith master Ibn Hajar said of him: “Unknown.” (3)

The hadith master Ibn Kathīr disagreed regarding him, saying: “This hadith is well known through Muhammad ibn Khālid al-Jundī al-Sanānī, the muezzin and a teacher of al-Shāfiī, and those who narrated from him also included