Network delay. A code fast line refers to a code pass, is a health code under the epidemic, is based on personal health data by the individual declaration, background big data information comparison generated by the personal exclusive two-dimensional code, the code WeChat sweep not on is due to network delays caused by slow transmission of information can be solved by connecting WiFi and replacing the flow rate, WeChat is a Tencent company launched on January 21, 2011, a smart terminal to provide The first step in the process is to make sure that you are able to get the best out of it.