This is all I have to go on, from my AP. MAC address obscured.
Sun Dec 29 17:39:52 2013 daemon.info hostapd: wlan0: STA de:ad:be:ef:de:ad IEEE 802.11: authenticated
Sun Dec 29 17:39:53 2013 daemon.info hostapd: wlan0: STA de:ad:be:ef:de:ad IEEE 802.11: No WPA/RSN IE in association request
Every time I try to connect, that's the only indication I can see that anything's even happening. The Zero is the only device with any trouble connecting to my setup, and I've had it up and running for a couple of years. The AP's running a recent build of Openwrt with 802.11n hardware.