PLY or Polygon File Format was designed to store data obtained from 3D scanners. It contains the information not only about the form, but also the color of the polygons. To display the PLY file correctly, colors of the model should be attached to its vertices. In some cases, colors may be stored in a separate file along with the textures. If this is the case, before uploading the file you should attach colors to the vertices of the model. This can be done, for example, in MeshLab. In the main menu, press Filters/Color Сreation and Processing. Choose either Transfer Color: Face to Vertex, or Transfer Color: Texture to Vertex.