Who works in the V-Ray version is lower than 3.1. Be careful, the materials in the BRDF section are Microfaset GTR (GGX), if your version is older than 3.1, then the BRDF field will be empty. Choose Blinn, Phong or Ward - which is preferable for you. "
: "For Corona render, it is recommended to put a version no lower than 1.5, since the glossiness of materials is adjusted to the PBR."