The Internet connection may be unstable, and the latest update file for the application cannot be found.
Please try the following steps in order to see if there is any improvement.
・Restart your PlayStation®5 and connect to the Internet using a wired connection as much as possible. And configure the network settings again.
・When using a wireless connection, review the installation location such as bringing your PS5 closer to your router or removing anything interrupting the connection between the devices.
・Turn off your router and modem, and wait at least 5 minutes, then restart it.
・Update the firmware of your router. (For details on how to update, please contact the router vendor.)
Please connect PS5 to the internet and install the latest update file.
If the above won't solve the problem, the line is likely to be temporarily busy. Please leave it for a while and try again later.