A secure webpage may be prevented from loading an insecure media resource. This browser protection can explain why a catalogue appears but playback fails. The site operator should provide a compatible secure media path rather than asking viewers to weaken browser security.
Use the browser message
A visible warning or developer-console message can distinguish mixed content from an ordinary unavailable stream. Do not publish the full media URL when it includes credentials. A redacted description is enough for initial support.
Keep the fix at the source
Changing browser flags to permit insecure content can expose requests and will not help every visitor. The operator needs to align the page, API and media delivery with supported security requirements.
Compare supported playback options
A native app and browser may handle connections differently, so success in one does not prove the other should behave identically. Use a documented player while reporting the browser-specific problem to the website operator.