Solid/Shell run error

Hii SolidWorks users,

I'm attempting to run an analysis with a shell attached to a solid. But for some reason, I keep getting this 'not valid' error (see below image).

I checked the contact set and it is set to Bonded, ie with the surface edge and the cylinder face. But it still doesn't work..

Does anyone know what might be causing this problem?

Thanks,

David

SolidworksSimulation