这个是检测网络联通性&generate_204服务的问题，连接手机执行以下命令：

adb shell "settings put global captive_portal_https_url https://captive.v2ex.co/generate_204 "

也可以将命令中的网址替换成以下几个：

Apple1 http://captive.apple.com
Apple2 http://www.apple.com/library/test/success.html
MicroSoft http://www.msftconnecttest.com/connecttest.txt
Cloudflare http://cp.cloudflare.com/
Firefox http://detectportal.firefox.com/success.txt
V2ex http://www.v2ex.com/generate_204
小米 http://connect.rom.miui.com/generate_204
华为 http://connectivitycheck.platform.hicloud.com/generate_204
Vivo http://wifi.vivo.com.cn/generate_204