Since you used a quote from the documentation without mentioning what you're trying to do, I assume you're trying to use the Barcode Scanner?
To use it locally, you need an https connection. The answers in this forum thread explain some ways to achieve that.
Keep in mind that specific steps and configurations may vary depending on the proxy tool you select and the specifics of your Mendix application. And even if you buy proxies, you still need to pay attention to the finer points. Refer to the documentation of your chosen proxy tool and Mendix for more detailed platform-specific instructions.