I have had this problem before. If you are sure that your model has not exceeded the element limit, it might be b/c of the error flag in the solution logs that were set to on, the first time your model exceeded the element limit, and after that even if you modify the mesh to stay below the limit, you will see the same error message. The solution is simple and you have to reset the error flag which can be done by resetting the model cell in the project schematic. or starting everything over from importing the CAD. I haven't tried the reopening the whole ANSYS project, it might work as well.