Ah. I didn't realise that this setup was working previously. If you still have or can re-generate the OpenFOAM case that was created (the "case" directory that is written), that would probably tell us why.
I have been using FreeCAD 0.17 and CfdOF for a year with great results. Recently moved to FreeCAD 0.8 and now having problems with Paraview 5.4.1. It will load from FreeCAD and from my Praview icon but I cannot do anything. It crashes and hangs up of I try to load a state or select open. It just sits there with no response and I have to end the task to shut it down. So I downloaded PV 5.4.1 but no change and then downloded PV 5.7.0 and it works fine. But I can't run it from CfdSolver or import my CfdOF case into this later Paraview version. So I'm confused, is there a way to get CfdSolver to start PV 5.7.0?
You should probably ask in the FEM/CFD subforum. I know that the CfdOF project is under heavy development, so Oliver, the developer, generally recommends to try with the latest version of CfdOF, Paraview, and OpenFOAM, so that everything works okay. Also trying with the latest version of FreeCAD, 0.19.