환경설정 작업 오류

안녕하세요. 오늘 처음 안드로이드 스튜디오 다운받았고, 처음으로 플러터 sdk 다운받았습니다. 그런데 에뮬레이터를 실행하고 test_proj를 실행하는 과정에서 아래와 같은 오류가 발생합니다. ㅠ.. 어떻게 해결해야 하나요?

4번째 Warning 부분이 빨간색으로 나오네요.

Launching lib\main.dart on sdk gphone64 x86 64 in debug mode...

Running Gradle task 'assembleDebug'...

Warning: This version only understands SDK XML versions up to 3 but an SDK XML file of version 4 was encountered. This can happen if you use versions of Android Studio and the command-line tools that were released at different times.

Checking the license for package Android SDK Tools in C:\Users\suhol\AppData\Local\Android\sdk\licenses

License for package Android SDK Tools accepted.

Preparing "Install Android SDK Tools (revision: 26.1.1)".

"Install Android SDK Tools (revision: 26.1.1)" ready.

Installing Android SDK Tools in C:\Users\suhol\AppData\Local\Android\sdk\tools

"Install Android SDK Tools (revision: 26.1.1)" complete.

"Install Android SDK Tools (revision: 26.1.1)" finished.

Checking the license for package Android SDK Build-Tools 30.0.3 in C:\Users\suhol\AppData\Local\Android\sdk\licenses

License for package Android SDK Build-Tools 30.0.3 accepted.

Preparing "Install Android SDK Build-Tools 30.0.3 (revision: 30.0.3)".

"Install Android SDK Build-Tools 30.0.3 (revision: 30.0.3)" ready.

Installing Android SDK Build-Tools 30.0.3 in C:\Users\suhol\AppData\Local\Android\sdk\build-tools\30.0.3

"Install Android SDK Build-Tools 30.0.3 (revision: 30.0.3)" complete.

"Install Android SDK Build-Tools 30.0.3 (revision: 30.0.3)" finished.

√ Built build\app\outputs\flutter-apk\app-debug.apk

Installing build\app\outputs\flutter-apk\app-debug.apk...

Debug service listening on ws://127.0.0.1:50981/764n9IlfL4k=/ws

Syncing files to device sdk gphone64 x86 64...

Lost connection to device.

adb.exe: device offline