Your defrost drain is plugged and not allowing the water from the defrost cycle to drain to the condensate pan, located below the cabinet by the compressor. That drain is positioned under the evaporator coil in the freezer, behind the rear wall. You can totally disassemble the freezer to remove the rear wall and manually thaw it, or just turn the unit off for about 12 hours with the doors open, a much easier solution. Of course, the food will need to be moved to a different location.

It sin't the ice maker or the ice cube tray would have to be full and leaking. The drain is at the back of the freezer, behind the panel shown as number 11 below. It will require all components to be removed from the freezer to get that panel off.