The answer to 'supply line not working' is that there are several common causes, including a clogged or damaged supply line, a problem with the shutoff valve, or an issue with the water pressure. Symptoms may include no water flow, low water pressure, or leaks around the supply line. Solutions can range from simple DIY fixes to more complex professional repairs, depending on the root cause.
If the supply line is clogged, you may be able to clear it yourself using a plumber's snake or by disassembling and cleaning the line. If the shutoff valve is stuck or leaking, you may need to replace it. More serious issues like a damaged or corroded supply line may require replacement by a professional plumber.