DNS Servers are often the cause of App Issues on LG Smart TVs. You may see apps disappear, give error messages, or appear in your Home Launcher Bar, yet refuse to open.
Setting manual DNS servers may also resolve "App needs to updated" messages, especially if trying to perform the update fails.
A DNS server converts the web adress name (www.google.com), into a web address ip (188.8.131.52). Like any other server, sometimes DNS servers go down, or don't reconcile correctly, and devices get confused.
Your best bet to resolve this issue is to set your DNS locations manually. Luckily, Google hosts public DNS servers for anyone to use.
Google's public DNS servers are 184.108.40.206 and 220.127.116.11.