Those who work in V-Ray version lower than 3.1, be careful, in the materials in the BRDF section there is Microfaset GTR (GGX), if your version is older than 3.1, then the BRDF field will be empty. Select Blinn, Phong or Ward - what is preferable for you

For Corona render, it is recommended to install version no lower than 1.5, since the glossiness of materials is configured taking into account PBR