One of the most common reasons your toilet will not flush is because the chain that connects the toilet handle to the flapper may have come loose and no longer is connected. When this happens your toilet will not flush because there is no way for the water in the tank to be used for flushing since the chain cannot open the flapper and allow the water to be dumped into the toilet.
What you will want to do is to remove the top of the toilet tank lid and look inside the toilet tank to first see if this is your problem. If you do find the toilet chain has come loose you will want to reconnect it to the flapper or the toilet handle. In some cases the flapper could have gone bad and the eyelet that the chain hooks on to will no longer be able to be used and you will have to replace the toilet flapper before reattaching the chain.
Check The Toilet Flapper
The toilet flapper is what the toilet handle and chain are connected to. If your toilet chain is not connected to the flapper your toilet bowl will not flush. Sometimes the chain will become loose from the toilet flapper when the toilet is flushed to hard. Another reason the toilet chain could have been disconnected from the toilet flapper is because the flapper eyelet that holds the chain on could have worn away from age. The toilet flapper is only made from rubber and after time it can and will rot away. Something else to look for is a toilet chain that is adjusted to tight. If your toilet chain is not adjusted the right way it could disconnect itself from the flapper everything the toilet bowl is flushed.
Make Sure You Have Water To The Toilet
If you do not have a water supply to your toilet bowl it will not flush. Sometimes the supply valve could be in the off position and you will need to place the water supply valve in the on position instead. You can put the toilet supply valve in the off position by turning the valve to the left which is counter clockwise. You must also make sure that the water main is also on. You could have a closed water main and even know you turn on the toilet supply valve in the bathroom you may not have water in the trunk lines.
You Could Have A Toilet Stoppage
If you have water to the toilet and your chain is on the toilet flapper and on the toilet handle and your toilet will still not flush you may have something called a toilet stoppage. A toilet stoppage is when something that has been flushed down your toilet has now caused a blockage and is preventing the water from being flushed through the toilet trap and causing your toilet now to work. You can use a toilet closet auger, a plunger or even a small hand snake to remove the blockage from the toilet bowl. Once you remove the toilet stoppage from your toilet bowl your toilet should flush again.