3 verses have
cannot
in Edition Clear Qur'an by Talal Itani / Al-Anbiyaa (The Prophets)

21:39If those who disbelieve only knew, when they cannot keep the fire off their faces and off their backs, and they will not be helped.

21:43Or do they have gods who can defend them against Us? They cannot help themselves, nor will they be protected from Us.

21:45Say, “I am warning you through inspiration.” But the deaf cannot hear the call when they are being warned.