If desktop application doesn’t start automatically when you click “Join” or “Host” on the web page and WebViewer starts instead - read this post to find how to fix it.
The main reason why browser doesn’t start the application is that it doesn’t know that the application is installed on your computer. The browser simply can’t check files on your file system because it would be a security violation. In order to tell the browser that you have the application - you need to download AND run it from this browser manually (www.freeconferencecall.com/downloads). In this case the browser will memorize the fact that application is installed and it will be trying to run it next time.
Running the browser in Incognito mode effectively erases all previous memory from the browser and it will be not trying to run the application again.
If you switched the browser you’d need to download and run the application again as different browsers does not share their memory.
Hope it helps