Current connection and settings don´t open

Hi, I'm having this problem too, I'm able to open these pages with Firefox (version 70) but not with Chrome (version 78), it returns the error ERR_INVALID_HTTP_RESPONSE
I was able to open the pages with Chrome briefly after clearing the DNS cache inside the menu chrome://net-internals/#dns but after a page refresh the error come back.

I also can type http://localhost:1487/cfosspeed/console.htm in firefox and it opens the graph correctly.

I don´t think you are reading my message thoroughly.

If port 1487 is being blocked or the cfosspeed service is not running
then why is the right click menu working with vivaldi, edge or ie as
default browsers and not with firefox?

Maybe some other program uses the local port 1487?

is the cFosSpeedS service running? You can check with
sc query cfosspeedS
you need administrator rights to check this.

If I right click on the cfosspeed tray icon and select "current connections" nothing happens.
If I right click on the cfosspeed tray icon and select "get latest version" nothing happens.
If I right click on the cfosspeed tray icon and select "options/settings" nothing happens.

Same for any other option requiring a browser window.

So far this only happens if firefox is set as the default browser, Edge and IE work fine.

Why? What is the error?

I just clean installed win10 (1903) and cfosspeed wont open current connections, settings or any other option requiring a browser window.