Make sure that Publicly Secure Packet Forwarding (PSPF) is not enabled.
PSPF prevents client devices associated to a bridge or access point from inadvertently sharing files with other client devices on the wireless network. PSPF provides Internet access to client devices without providing the other capabilities of a LAN.
To enable or disable PSPF, refer to these documents:
To block access between the clients connected to different access points on the same switch configure the ports to which the access points connected as a Protected port. Refer URL Configuring Protected Ports for configuring this.
Associated but cannot pass traffic to some devices
WLAN adapters (wireless card) / ACU (Aironet Client Utility)