Multiple media can not be played

multiple media can not be played appears at bottom for most of Redbox apps. Using Nvidia Shield. Can not find settings. TY

That usually indicates that there is already “medium” loaded into the vid player and it did not shut down and clear it’s IO state properly. What ever vid player you are using go into it in settings, force close, clear cache. See if that clears the “Multiple media” warning. If not then force close, clear data, redo any changes you may have made to player options, retry.