Hello there, I was having the very same issue and that’s when I researched and found your thread. Not having read a straightforward fix to my problem here, I dig more intro the matter.
You didn’t give infos about your system but it seems you are using a machine running Windows so I assume you have the WASAPI driver installed.
I had noticed that Kontakt, used as a stand alone, didn’t give me any issue (while running it, I could watch YouTube, use media players etc). I knew I was using the WASAPI driver there as I was in Cantabile, but I realized that Kontakt gave the option to select WASAPI SHARED MODE, which Cantabile, apparently, didn’t offer. At this point I knew where the problem lied. All I had to do was find a way to run Cantabile with WASAPI in SHARE MODE but I didn’t know how. So I continued my search and that’s what I’ve found: https://blog.cantabilesoftware.com/wasapi-improvements-e897abee462b/
In a nutshell, in Cantabile, I selected WASAPI as the Audio Driver and then in the Sample Rate field I selected SHARED MODE. And voilà, problem solved! I hope you will find this helpful. Cheers!