Does anybody know if the speed test app on the desktop working properly
https://www.verizon.com/speedtest/
I don’t know what you are referring to about on your desktop.
above is the link to test speed only if using a verizon router. It does not operate with a customer owned router unless it’s in bridge mode (Verizon router first, owner owned second)
for speed tests with your own router or even verizons you can try
http://www.speedtest.net