We read in Al-Fatāwā al-Ḥadīthiyyah by Ibn Hajar al-Haytami, page 123:
"As for the jinn, the Ahl al-Sunnah believe in their existence. The denial of their existence by the Mu‘tazila is in opposition to the Qur’an, the Sunnah, and consensus. In fact, some of them went so far as to declare it disbelief(Kufr), because it entails denying the clear textual evidence of their existence."