Why does the pan/cistern installed not take waste/paper away?

Why does the pan/cistern installed not take waste/paper away?

There are a number of things which could cause this:

1 - The holes of the rim on the box-rim pan could be blocked (inspect and unblock holes)

2 - If the problem is occurring on a lever-flush cistern then the diaphragm washer could be worn away or torn and will need replacing.

3 - The tail of the siphon that sits into the top of the pan may be too long and touching the ceramic in the top of the pan causing air locks and restricting the flow of water into the pan. (The siphon or drop valve tail will need to be cut off level with the siphon or drop valve back-nut)