It was recorded by ʿAbd Allāh ibn al-Imām Aḥmad in "Kitāb al-Sunnah" (p. 186), and its chain is good, and the ḥadīth is authentic through its various routes.

the holder of the trumpet has been ready since he was entrusted with it, looking towards the Throne out of fear that he might be commanded before his glance returns to him, as if his eyes are two shining stars. It was recorded by al-Ḥākim (4/558-559) through the route of Muḥammad ibn Hishām ibn Milās al-Namrī, who narrated to us from Marwān ibn Muʿāwiyah al-Fazārī, from ʿUbayd Allāh ibn ʿAbd Allāh ibn al-Aṣamm, who narrated to us from Yazīd ibn al-Aṣamm, from Abū Hurayrah, who said: The Messenger of Allāh (ṣallá Allāhu ʿalayhi wa-sallam) said it, and he mentioned it. He said: "The isnād is authentic," and al-Dhahabī agreed with him and added: "according to the criteria of Muslim"! I say: al-Ḥākim was correct, but al-Dhahabī erred, for al-Fazārī is among the men of Muslim but not his teachers, and Ibn Milās was not included by Muslim at all, and he is truthful as Ibn Abī Ḥātim said (1/4/116), so it is not according to the criteria of Muslim then. It was deemed good in "al-Fatḥ" (11/368), and his explanation is that al-Ḥākim proceeded in his book "al-Mustadrak ʿalá al-Ṣaḥīḥayn" by authenticating the isnād according to the criteria of the two Shaykhs or one of them, considering their teachers or one of them, meaning that al-Ḥākim's men to the Shaykh are trustworthy, and his isnād to him at least is authentic, but not according to their criteria because they are below them in rank obviously. So if we want to match al-Ḥākim on this terminology, the isnād of the ḥadīth must end with a teacher of al-Bukhārī and Muslim or one of them to correctly say it is according to their criteria. If the isnād, which is according to the criteria of Muslim, for example, as here, ends with a narrator from Muslim's narrators who is the teacher of the narrator who is from the rank of Muslim's teachers and not actually his teacher, as is the case with Ibn Milās, then in this case, it cannot be said that it is according to the criteria of Muslim. Perhaps what makes the matter clearer is that if we assume that an isnād of al-Ḥākim ended with Saʿīd ibn al-Musayyib from Abū Hurayrah, and it is known that Saʿīd and Abū Hurayrah are among their men, but al-Ḥākim's isnād to Saʿīd is not according to the criteria of the two Shaykhs, meaning they did not include his men in their Ṣaḥīḥayn