Don't ever hook up LEDs to an unregulated power supply, the LEDs will try to pull as much current as they can. Hopefully you just blew one LED up and not all of them. I also don't think BuckPucks can handle more than 32VDC, so that may be an issue since the adapter could be producing a higher voltage at startup, frying the BP. If all six of your LEDs are in series, you don't need more than 24VDC and, depending on the BP, 1.5Amps. The BP will limit the current and provide the appropriate voltage.