Are you certain that your default layout is valid? (checkmark in layout status in CMS) - you can send the layout to us if want us to check it.
You can also go to ‘Modules’ page and run ‘verify all’ routine. Then restart your player and give it a moment.
How is your display represented in the CMS displays page? Is it logged in and up-to date?
Why won't my layout play? / The splash screen plays instead of my layout