Allow few origins to access openvidu server.
It depends how you deploy OpenVidu platform. If you use a proxy (to manage SSL certificate), then CORS should be configured on the proxy.
If you do not use a proxy, then you should recompile OpenVidu-server as CORS only can be specified in code.
Take a look here: https://stackoverflow.com/questions/42874351/spring-boot-enabling-cors-by-application-properties