Just for clarification, the self-signed certificate used by Resilio Sync is completely adequate for security purposed, and does not require replacement with your own private certificate, which is optional, and the process to use your own certificate is detailed within this forum. Just realize that doing this is not required, it is only necessary to follow the instructions given above to create the exception to allow your browser to access the site. You also need to repeat this process for any browser on any computer or mobile device you use to access the WebUI for Resilio Sync.