wlan0 keeps going DOWN on its own

New FreeBSD install (and new to FreeBSD). My DELL Latitude's wlan0 keeps going DOWN on its own. Running dmesg only shows this:

Limiting closed port RST response from 203 to 200 packets/sec
wlan0: link state changed to DOWN
ifa_del_loopback_route: deletion failed: 48

What else can I do to troubleshoot this?
What version of FreeBSD? What driver is used for the wireless card? What's the brand/model/type of the card?