Some low-flow or water-saver toilets have this problem. Flush the toilet and hold down the flush lever until all the water has drained from the tank. Did this clear all the waste? If so, then the toilet has enough flush capacity, but the flapper valve may be closing too early. Try replacing the flapper with a new one.
The search for people who can answer your question continues for as long as needed - until you find the answer you were looking for.
When an answer is posted by someone who was invited (byYedda or by yourself) to answer your question, their answer is marked with a yellow "invited by Yedda".
To be invited to answer other people's questions in your areas of knowledge and interest, be sure to list your favorite topics:
» My Settings My Topics.
Of course, the more helpful your answers are, the more likely you are to be invited to future questions...