The answer to 'toilet won't flush' is that there are several common causes, including a clogged toilet, a problem with the flush mechanism, or low water pressure. Symptoms may include the toilet bowl not filling with water or the water not draining properly. Solutions can range from simple DIY fixes to calling in a professional plumber, depending on the underlying issue.
Some common causes and solutions include: a clogged toilet (use a plunger or plumber's snake to clear the blockage), a faulty flush mechanism (replace the flapper, fill valve, or other components), or low water pressure (check for any leaks or issues with the water supply line).