Shaykh Ahmad insisted that the authority for his teaching came from his direct contact with the Imams in the realm of visions

The school that was eventually to emerge from the teachings of Shaykh Ahmad is usually called the Shaykhi school, although it should perhaps more correctly be called the Kashfi school. At this time, however, it was not a separate school, but rather a distinctive teaching that Shaykh Ahmad was giving. [...] There was particular concern over some of his teachings that implied that many of the theological tenets of Shi'ism such as the occultation of the Hidden Imam and the resurrection should be understood as occurring in a subtle spiritual world rather than in the material world. Perhaps most worrying of all for the orthodox Usuli scholars was Shaykh Ahmad's insistence that the authority for his teaching came from his direct contact with the Imams in the realm of visions-the truth was uncovered or revealed (kashf) to him in these visions. This was at direct variance with the Usuli insistence that truth should be obtained by ijtihaid and through rational processes.

-Moojan Momen (Usuli, Akhbari, Shaykhi, Babi: The Tribulations of a Qazvin Family)