Suppress connection errors in airplane mode

app/src/main/java/eu/faircode/email/ConnectionHelper.java

@@ -11,6 +11,7 @@ import android.net.Network;
 import android.net.NetworkCapabilities;
 import android.net.NetworkInfo;
 import android.os.Build;
+import android.provider.Settings;
 import android.telephony.TelephonyManager;
 
 import androidx.preference.PreferenceManager;
@@ -300,4 +301,8 @@ public class ConnectionHelper {
         return null;
     }
 
+    static boolean airplaneMode(Context context) {
+        return Settings.System.getInt(context.getContentResolver(),
+                Settings.Global.AIRPLANE_MODE_ON, 0) != 0;
+    }
 }

app/src/main/java/eu/faircode/email/ServiceSynchronize.java

@@ -665,7 +665,7 @@ public class ServiceSynchronize extends LifecycleService {
                         ConnectionHelper.connect(this, istore, account);
                     } catch (Throwable ex) {
                         // Report account connection error
-                        if (account.last_connected != null) {
+                        if (account.last_connected != null && !ConnectionHelper.airplaneMode(this)) {
                             EntityLog.log(this, account.name + " last connected: " + new Date(account.last_connected));
                             long now = new Date().getTime();
                             long delayed = now - account.last_connected - account.poll_interval * 60 * 1000L;