It sounds like the power saving feature might be turned on. You can turn this off through the on screen menus. More details can be found in the owner's manual. If turning power saving off doesn't resolve the issue, I suggest resetting to factory defaults (you can do this without erasing uploaded photos), ensure that demo mode and power saving are turned off. Please let us know your results!
Regards, John Insignia™ Support
John|Social Media Specialist | Best Buy® Corporate Give Kudos if you like this post or Accept as Solution if it answers your query!