Would you please provide the version information for your Webex app @nbiancuc? You might also try doing a network test. Here's a link to the Cisco Webex test for meetings that will help to eliminate that the problem is caused by your network connection.
https://mediatest.ciscospark.com/#/main
You may also want to check your computer's memory and CPU usage to make sure neither one is running at a high level. You can shut down some unneeded apps and services to help to reduce these if needed.
