FWIW. I had this same issue. Took the vehicle to a local garage (not the dealer), who cleared the line and charged $35. I live in Virginia, where the humidity is rather high at times. With the A/C at full tilt, it took three days to clog again and the sloshing sound returned. It's not a tough fix at all. The tube crosses from the passenger side of the car, to the drivers side of the transmission tunnel. You can absolutely do this yourself. You'll need an empty medium size mixing bowl, a container with a cup or two of warm water with a little bleach in it, and a turkey baster (hello dollar store)... It's been a while since I've needed to perform this task and am giving it to you from memory, but this should cover the main points.
The center console of my 2007 Edge has removable lower panels, YMMV.
Remove the lower panel on the driver side of the center console. This should reveal the rubber hose/plastic elbow that allows the condensation to drain from the vehicle. You may need to pull the carpeting back just a touch to reveal it. It'll be pretty obvious.
Grab your empty mixing bowl to catch the water. Pinch the rubber hose and remove it from the plastic elbow at the floor. It should just slip off as there's no pressure or vacuum in the line. Over the bowl, allow the water to drain from the system.
Fill your turkey baster with as much of your weak bleach solution as it will hold. I mean, fill the bulb and tube with as much as you can. Press the nozzle of the baster into the end of the rubber hose and carefully push your disinfectant/deodorizer back through the line. Squeeze the bulb of the baster several times, gently pushing the disinfectant in and sucking it out of the hose and system. This not only helps to eliminate awful odors, but dislodge debris in the line.
Grab your drain bowl one last time and pinch the hose as close to the baster as you can. Drain everything into the bowl and discard. You'll likely see flecks of gunk in the water.
Reconnect the drain hose to the plastic elbow (else your driver side floor will fill with water), and reassemble.