Water dispenser not working

Brand: Frigidaire
Model Number: FHGB2866PF4
Main Symptom: water dispenser no working
What happens & when: no water flows when I press the dispensing button.

Error Code (if any):
Parts or tests already tried: I have tested the yellow connector and it has power. I have used the yellow connector to test the main intake valve and water flows through to the brown line. I have tested the return line from the filter and water flows. I have used that return line to test the line to the dispenser and that line works. It now appears that the line from the tank back to the secondary valve body is not providing water back to the secondary valve. I used the detailed test instruction provided with a new valve to determine that the valve is not defective. After reading many of the other posts, I became suspicious that the issue was with the water tank, so I inspected the foam insulation on the back of the fridge carefully and found ice in the hole in the upper right side and when the insulation was pulled away I found rust on the back of the fridge.
Photos / video link: Dropbox

Based on the information and photo you provided, we suspect the water tank may be leaking, preventing water from reaching the dispenser.

Is the refrigerator still producing ice? If it is making ice normally, that tells us that everything up to the diverter portion of the water valve is functioning properly, which helps isolate the issue to the dispenser side of the system.

If ice production is normal, the most likely cause would be a leaking or damaged water tank https://www.appliancepartspros.com/frigidaire-water-tank-242220501-ap5949945.html