1.
Water supply problems in the tank: First check the water supply in the tank. Make sure the water valve is open and check that the water pipe is properly connected to the tank. If the water source valve is open and the water pipe is connected properly, but the water still does not enter the tank, there may be a problem with the water supply.
2.
Valve failure: There is a valve inside the toilet tank that controls the flow of water, usually a float or plunger valve. If the valve is damaged or stuck, it will prevent water from entering the tank. Check that the valve is working correctly to ensure that it can move freely and control the flow of water.
3. Internal problems in the tank: Sometimes parts inside the tank may fail, such as floats or chain breaks in the tank. Check the various components inside the tank to make sure they are intact and properly connected.
4. Clogged or leaking problems: There may be a blockage or leaking problem between the toilet tank and the drainage line. Check that the drainage holes at the bottom of the tank are blocked, and that the water pipes and drainage pipes are leaking.
If you are unsure how to fix the toilet or have a complex problem, it is recommended to consult a professional plumber or toilet repair specialist who can help you diagnose the problem and provide a suitable solution.