Not only from some sites.. from literally nowhere. I am running on El Capitan 10.11.16
Could you please send through a log file the next time this problem occurs?
You can find the Jaksta log file by going to the Preferences and clicking the Find Log File button.
I have the same problem and my internet connection stops. something really not working when i turn jaksta media recorder on. Running on Sierra 10.12.3 Media recorder Version 1.5.1 (205)