It's a built-in feature of the iPhone. Save power! If you use WiFi to download software or update software, even if the lock screen will work. But it doesn't work if you're using Kugou to download songs.
After the WiFi manager updated the new version, the lock screen broke the network, the situation of uninstalling the wifi manager lock screen broke the network did not happen, and later updated the two versions and re-installed and used, and found that the lock screen broke the network again, each time after uninstalling the WiFi manager, this phenomenon disappeared. It does not rule out other reasons, but it is recommended to uninstall it first.