I keep getting this message when I load from my mycloud pr2100. I have a fresh start of windows 10 and the NAS is brand new as well. I got it specially for the plex features. I use Google Chrome for surfing and i have tried everything I have run across and nothing works. If I cant get answers I am taking it back.
can you try to browse to http://192.168.1.185:32400/web I would assume that configure button would direct you to the same place but can you type that into your browser and see if you get the same results?
I was getting same error on some movie site, then I tried bunch of command prompt commands and eventually it workout for me and it can also help you out.
Open command prompt and apply this commands one by one:
ipconfig /release
ipconfig /all
ipconfig /flushdns
ipconfig /renew
netsh int ip set dns
netsh winsock reset
Hopefully this will also work for you too and then you will be able to configure plex through chrome.
If this didn’t for you then you can refer to err_connection_refused for more solutions