As you are working with a hybrid app, you need to determine which context you are in before you interact with the specified element, WEBVIEW or NATIVEAPP and make sure that you switch Appium to use that context.
If you are working with WEBVIEW, try looking up the standard WebDriver locators for you language bindings. You should hopefully have better luck in WebView using id, name, class, css, link_text, partial_link_text, and XPath.
How you declare these locators will depend on the language you are using.