Fix the ANSYS meshing error: "One or more entities failed to mesh"

This is quite a small, quick project. I have a file that I am trying to run a CFD on through ANSYS that I need quite urgently, however when I try and mesh the file I get the error: "One or more entities failed to mesh. The mesh of the bodies containing these entities may not be up-to-date. However, meshing might be successful on the other entities". I only get this problems with the model when meshing in ANSYS. I can run an FEA fine on it in Solidworks without any such errors, and I have triple checked that the model is sound. I would like to know what steps are needed to fix the problem. The files were created in Solidworks, which I will supply.