Here are some other possible solutions that you could try:
Check if the router is blocking the TV by MAC address. You can do this by logging into your router's settings and checking if the TV's MAC address is in the allowed list.
Ensure that other devices connected to the same network can access the internet. You can do this by plugging a laptop into the same network cable.
Try restarting both the TV and the router by switching them off and on again.
Check if there is a software update available for your TV. You can do this by going to the TV settings and selecting "System Update".
If your TV is connected to the internet through a wired connection, ensure that the Ethernet cable is securely connected to both the TV and the router.
If you are using a wireless connection, try connecting the TV to a different Wi-Fi network and check if the issue persists. If it does not, then the problem could be with your router's settings.
If none of the above solutions work, it could be a hardware issue with your TV. In that case, you may need to contact Panasonic customer support or a professional technician for assistance.
I hope one of these solutions helps you resolve the issue with accessing apps on your Panasonic Viera TV.