Error - No punch cutoff sections found

Hi,

I'm a relatively new user and having an issue with the error message below;

 

It is happening for all of my edge columns. I've played with the geometry, trying a flat slab, with an edge thickening and varied the punching shear "maximum search radius". The only fix I've found is moving the columns significantly away from the slab edge (>300mm), I made sure they were fully under the slab before starting.

Any advice?

Regards,
Liam