I get "Server (URL) connection timeout", "Check playlist URL" or "No playlist uploaded" messages, when starting the app, while my playlist URL that works on my computer, other devices and apps.
Try example test list
http://sip******* WARNING FRAUD **DON'T BUY** PLEASE REPORT TO ADMIN *******/lists/example.m3u (external URL) first, then then check your playlist for errors. Make sure your URL is a direct link, not a redirect and that it is currently online. You can also try downloading your playlist file by putting the playlist URL in the internet browser address field and use it as a static playlist at My list page.
In case of Check playlist URL you can try turning off your TV/device from power for ~1 minute to clear device cache.
Additionally, try reducing your playlist size by removing channels/movies (especially if you have LM series LG TV with limited memory). If your playlist doesn't appear on TV or disappears after restart, try checking Save online box, when uploading the playlist. You can also try resetting Smart HUB or turn your TV off and on to clear the TV cache if you have.
You can also try to change buffering size in the main menu ( Red button) from large or auto to medium.