=>no cached version of com.android.tools.build:gradle:3.6.3 available for offline mode.

        use gradle version updated one......  and plugin version also updated version.

     check the updated version by click the link.

https://developer.android.com/studio/releases/gradle-plugin

=>Unknown host services.gradle.org. You may need to adjust the proxy settings in Gradle.

File->settings->Appearance and Behaviour-> system settings -> No proxy

 if again the error is occured it is Network error.

           go to Control Panel....then turn off the firewall ...  refer the screenshot.

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