Check if the response is null rather than if it's 200 code

Assets/Scripts/AccountMenu/AccountChangeUsername.cs

@@ -39,7 +39,7 @@ public class AccountChangeUsername : MonoBehaviour
         request.SetRequestHeader("ClientVersion", Application.version);
         request.SetRequestHeader("ClientPlatform", Application.platform.ToString());
         await request.SendWebRequest();
-        if (request.result != UnityWebRequest.Result.Success)
+        if (request.downloadHandler.text == null)
         {
             changeUsernameBackButton.interactable = true;
             changeUsernameSubmitButton.interactable = true;