I plugged it in but it keeps loading saying 'Please check connection', and it seems like the device is working OK, but it still does not do anything. What's wrong?
Based on the information I have found on the official website, this product is still supported. I recommend reading the questions on the FAQ page provided by the developer. According to their saying, you need to make sure that the software is allowed to communicate with Internet in the Windows Firewall or its alternative (3rd party).
Access the following page and read about connection problems and mostly everything offered by the uploader: https://www.diasend.com/global/support/faq-contact