1, the first possible reason is the router problem. If you suddenly disconnect, the settings should be correct, but the router is not working properly. Just restart the router.
2. Another possibility is that there are too many devices connected to the wireless router's WiFi, which causes great pressure on the wireless router, resulting in IP conflict and failure to connect. If so, you can set a static IP address for the mobile phone.
3. Then there is the problem of the mobile phone itself. Sometimes when a mobile phone receives a wifi signal and a connection, it cannot recognize the link because of the device itself. We just need to turn off the WLAN and turn it on again to connect, or cancel saving the network and enter the password again to connect.
These are the reasons why Huawei p9 can't connect to wifi. Friends who encounter such problems can learn about it and hope to help everyone.