Brim not connecting to printed model

I have the cobra 3 and I am happy printing some stuff for miniatures. But when I print large flat rectangular shapes the edges curl up. To solve that I am using the brim option in the slicer. But when looking closely you can see the groundplat between the lines of the brim and between the brim and the printed model. Anyone a ideas what setting this is. My first guess was first layer width but that did nothing.