Pretty well documented in previous posts for this problem.
Basically the top part of the dispenser housing is blocked. You need to strip it apart and clean it all out.
It could be the valve magnet (inlet valve) mine blocked but affected the soap side of the drawer. It rusted and began to leak- it was only at this time i noticed the problem.
Sorry, but that would give other problems, such as you had.
For conditioner both valves are opened thereby forcing water through the centre channel. It's an extremely common problem.
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