appium 启动 start session 的时候提示错误，求大神指点，刚刚接触 appium 卡在这一天了
Error
An unknown server-side error occurred while processing the command. Original error: Error executing adbExec. Original error: 'Command 'C:\android-sdk-windows\platform-tools\adb.exe -P 5037 -s 9bb17bf2 install C:\Users\Administrator\AppData\Local\Programs\appium-desktop\resources\app\node_modules\appium\node_modules\appium-unlock\bin\unlock_apk-debug.apk' exited with code 1'; Stderr: 'adb: failed to install C:\Users\Administrator\AppData\Local\Programs\appium-desktop\resources\app\node_modules\appium\node_modules\appium-unlock\bin\unlock_apk-debug.apk: Failure [INSTALL_FAILED_VERSION_DOWNGRADE]'; Code: '1'

{
"platformName": "Android",
"deviceName": "9bb17bf2",
"platformVersion": "8.0.0",
"appPackage": "com.woozoom.agrigcs",
"appActivity": "com.woozoom.agrigcs.activity.AGWelcomeActivity"
}