It's been a while since I performed a simulation using an internal fan. I'm currently working on an electrical enclosure which has been defined with environmental pressure boundary conditions at the lids (only the left most lid is shown below, the others are hidden by the section view). The fluid volume is generated correctly, and I have check this through Tools -> Check Geometry.
After selecting the fan type and inlet/outlet faces on my dummy fan model I'm getting an error that the fan face is not on the solid/fluid boundary. This doesn't make sense to me since an internal fan is intended to be entirely inside the fluid volume.
Does this seem familiar to anyone? Please let me know if I can provide any other relevant parameters of the simulation.