tdci puma water pump leaking oil

I'm getting a steady leak from the gasket between the water pump and the engine in my tdci. Is there a trick to this?

I am on my second gasket and don't want to ruin it. I'm almost certain the pump is fine.

Do people use gasket sealer? Am I doing something wrong?

Is this an area prone to leaks?

It is not a bearing doing it and I am positive it is coming from the seal.

Help would be greatly appreciated.