Add the INTERNET permission to your manifest file.
You have to add this line:
To perform network operations in your application, your manifest must include the following permissions.
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
outside the application tag in your AndroidManifest.xml
For Internet Permission:
<uses-permission android:name="android.permission.INTERNET" />
For Access network state:
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
For Access WiFi state:
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
Also Read:
Check Internet Connection on Flutter app