The answer to 'emergency plumbing won't flush' is that there are several common causes, including a clogged toilet, a problem with the toilet tank or flushing mechanism, or a blockage in the sewer line. Symptoms may include water not draining properly, a slow flush, or the toilet bowl not filling up with water.
Some solutions you can try yourself include using a plunger to clear a clogged toilet, checking the tank for any issues with the fill valve or flapper, and using a drain snake or auger to clear a blockage in the sewer line. However, if the problem persists or you're unsure of the cause, it's best to call a professional plumber who can properly diagnose and fix the issue.