What is the make/model number of this TV?
Are you using a Roku device with this TV? If so, do a system restart or unplug power for 60 seconds on the Roku. System Restart - Home, settings, system, power, system restart.
If this is an older TV, it is possible there are no more firmware updates for the TV, then most likely the old apps will no longer work and the newer apps are not compatible. I do not believe Panasonic makes TVs with a Roku operating system and I do not know what type of operating system it uses for apps. TV manufacturers are notorious for not keeping their operating systems up to date or supported and if this TV is more than a few years old, then that is likely the case.
You could try unplugging your TV from power for 60 seconds to clear the TVs cache and see if that helps. It is possible that the TVs operating system is obsolete, or the memory is corrupt and no longer working like it should. If the internal memory has gone bad and unplugging and/or factory resetting doesn't help, then you would need to contact Panasonic customer support directly.