I am sending it now via the support page

It seems that this Plugin "Inceptive Multiple Categories for K2" prevents pagination to work properly.
I have it now Disabled in your first site and the pagination shows.
You need to ask from the developers of that plugin to check on the issue.

We contacted user Dennis Miliopoulos several days ago, in order to ask him further info so as to help him resolve this issue.
Unfortunately he never contacted us back.
Recently another user contacted us with the same issue and we concluded that the user was trying to use our plugin along with K2Mart.
Our Inceptive Multiple Categories for K2 is currently not compatible with K2 Mart and there is no certain roadmap on when it will be.
We are at anyone's disposal to be hired and implement this compatibility for him.
Regards

I have the same problem now.
How do I find if some plugin messes with the pagination showing?

tnx,
Gorast