The connection to adb is down, and a severe error has occured.

在命令行中到xxxx\sdk\platform-tools\下輸入adb kill-server再adb start-server，仍失敗的話是端口被佔用，通過C:\Users\xxxxxx>netstat -ano | findstr "5037"命令進行查看佔用端口號，到任務管理器把該進程殺掉