Because there are knockoffs, parallel imports, clones, refurbished machines and so on. The IMEI number of mobile phones in the market can be changed by brushing, so it is impossible to accurately identify the authenticity and authenticity of mobile phones only by serial number, software testing, IMEI number and mobile phone origin. If you want to identify whether the mobile phone is genuine or not, please take the purchase invoice, warranty card and the machine to the nearest service center and ask the service center staff whether the machine can be repaired if it has performance failure within the warranty scope. If it can be repaired, the machine is a genuine licensed product. This is the best and most accurate method.