Product left in the dispenser drawer can be related to placement, residue, or lack of water flow. A small amount of water left behind does not, by itself, prove a faulty dispenser.
Identify what is left and when it was supposed to be used
Confirm the compartment you chose and whether the cycle uses that product. Prewash and fabric softener are not dispensed at the same time. Also check the liquid or powder insert and the siphon assembly according to the manual.
Do not exceed the fill mark. Check whether the product is too thick, gelled, or outside the storage conditions on its label. Do not dilute it out of habit: follow the product and appliance instructions.
Separate dirt from lack of water
The dispenser drawer and its siphon must be cleaned by the allowed disassembly method. Samsung links dispensing to inserts, maximum level, placement, and cleaning in its dispenser troubleshooting guide; its removal mechanisms are not universal.
If there is also little water coming in, check the water supply. If water is leaking out, use the diagnosis for dispenser drawer overflow. A clean compartment that still does not receive the expected water flow may need inspection of the dispenser, hoses, and valve.
Automatic dosing reservoirs work differently. When the fault affects that function, continue with auto-dosing not dispensing.
Check the compartment after the stage that is supposed to empty it; looking too soon can make a product seem stuck when it was not supposed to have entered yet.