Defrost trey and drain keeps freezing and water leaks inside

The first answer Katherine correct one with one exception; you do not have a problem in the defrost system because you are getting water from the defrost. You may have a clogged (and now frozen) drain, or a faulty defrost heater which supposed to keep the drain from freezing up.
Defrost the drain with hot water and make sure to test running water through the drain down to the drain pan. If it freezes after you cleaned it, replace the DRAIN heater only.
goodluck

the defrost drain pan is plugged up,you need to defrost it and run a wire down the drain tray hole so it can drain to the bottom as it defrosts otherwise it defrosts and runs everywhere else and re freezes

It's due to wrong temp setting and malfunction of defrost cycling. Keep thermostat setting at 5 degree or little less. And don't keep it in minus,as defrost cycle will take longer time. And also you will get less cooling in fridge compartment and also water leaks.Check drain line hose may freezed. And also freezer tray get blocked due to over frosting around freezer. Defrost manually by unplug your fridge and after defrost all ices, plug again and keep correct temp setting. Thanks.

I believe your defrost condensate drain has a blockage of ice and will need to be defrosted and clean the condensate line from the freezer to the condensate collection plate below your refrigerator. Most times the blockage begins slowly until the opening of the drain hole under the evaporator freezes itself shut. Below is a link to some solutions I have collected over a period of time. Also has a short movie that makes the repair look simpler. There are many reasons for this happening for example water leaking from a water supply line for the dispenser or ice maker, a crack in the defrost pan, water leaking inside and draining through the refrigerator cabinet, but most are caused by a defrost drain line blockage. Below is a link that may be helpful so try to take it all in and use the parts that most refer to your specific problem, Thanks Sea Breeze
click on link below

Clean out the defrost drain. There is a drain in the freezer that lets all the defrost water run under the fridge. If that gets clogged then all the water runs into the freezer and can even leak onto the floor

Inside the freezer at the bottom in the back there's a drain hole that must be clogged and the water from every defrost cycle freezes up and make it worse , so first pour hot water into the drain to melt the ice and keep pouring until it goes through .Keep the drain clean doing this every 3 or 4 months.

hi August.
Cause: A blocked defrost drain is one of the most common causes of water leakage. This happens when food particles or other debris clogs up the drain hose, which can lead to ice buildup and, eventually, water leaking out of the freezer and refrigerator.
3 common refrigerator problems you can easily fix yourself

The freezer drain hose will drain the defrost water into a drip pan at the bottom of the freezer. When this pan becomes full, it will leak water onto the floor. This is a regular maintenance task whenever the freezer defrosts. Empty the drip pan during the defrost cycle.
How to Fix Water Leaking From the Bottom of Freezer

Why is my fridge leaking water on the floor? If the refrigerator is leaking water it's possible that the refrigerator has a clogged or freezing defrost drain. If the defrost drain freezes the defrost water will overflow the drain and drip down to the bottom of the compartment, If enough water accumulates in the bottom it can run out onto the floor.
SOLVED Water leak in refrigerator Refrigerator

Hi. thanks for the question . The first thing i would do is clear the drain tube .that could be why the freezer ices up .too much moisture Clean the drain, And the coils at the back. thanks the appliance doc

It freezes up for a few reasons. First the water is not running down fast enough. That is why the wire was added to add heat from the heater to the drain hole. The metal pan under the evaporator coil may not be lined up with the drain hole well enough and holding water there. If that looks ok the drain tube that runs down the inside back of the unit might be slightly restricted. Not much you can do about that. I would make sure that the aluminum wire goes in the hole about 2 inches and that the unit is tilted slightly back to help water flow.

thius suggests the defrost system not working and the defrost drain blocked. take off the back panel inside the freezer, melt off excessive ice and free the drain at the bottom with hot water and patience