You need a cross-domain permission if your player loads text files such as .txt .m3u8 .mpd .vtt etc from a different domain. This host where loaded files are stored must confirm this action and can use a CORS for cross-domain permissions.
Try this guide if you are using nginx
You can find some manuals for server side here.
If the player can't load a document, look at the messages in the browser console (In Chrome it can be found in More Tools > Developer Tools) — there will be detailed information.
While working in security mode (HTTPS), all files must be downloaded using the same protocol.