Sony TV app keeps disappearing

Okay guys I really need you help I have an older model 4K TV 2014 to be exact lately when I try to log into the Plex application on my TV it tells me that the app with currently unavailable in the web store the TV is running the Opera operating system I have check for software updates everything is up to date on on the TV maybe there is a bug in the software if anybody can shed some light on the situation please help because I cannot access my Plex app on my Smart TV