Microsoft Edge users: For security, Edge will not allow a page loaded from an Internet site to open a network connection to devices on your local network. Therefore, this page can not test for the availability of HeaterMeter on your network. Understanding Enhanced Protected Mode (MSDN)
For security, as of Chrome 94 an Internet site can no longer open a network connection to devices on your local network unless both are running HTTPS. Therefore, this page can not test for the availability of HeaterMeter on your network.