Network problems. Huawei mobile phone downloaded my Yancheng page black and white screen because of network problems. There is no network, the network is not good, the application data cannot be loaded, and a black and white screen will be displayed. You can switch to a stable network and try again. "My Yancheng" App is a boutique urban life service platform created by the municipal party committee and municipal government, which integrates government services, public services and life services, creates a unified entrance for urban services, and provides citizens with "one-stop" government services.