Internet connection difficulties are usually an indication that your device does not have a routable IP Address - your IP Address usually being assigned by DHCP. When problems occur, your iPad may only have a self-assigned link-local IP address that begins 169.254.x.x.
You can verify your DHCP-assigned IP Address from settings:
Settings > Ethernet > [Your Ethernet Adapter] > IP Address
If you have a VPN App or profiles installed, or a security/AV/firewall App such as Norton, these may be interfering with DHCP and preventing your device from obtaining a valid IP Address for the network interface with which you are attempting to connect to your wired Ethernet network. The resolution is usually simple; if installed, you may only need to temporarily disable or remove the Security App and/or VPN.
DHCP is frequently used to automatically obtain an IP Address. Until your iPad has a valid IP Address to connect to your network, you will not have an internet connection. Disabling or removing VPN and/or the offending security App should allow DHCP to operate normally - allowing connection to your network and the internet.
If this resolves your issue, the VPN and/or security App can be reinstated after the connectivity problem has been resolved.
You may find that a restart of your WiFi Router, followed by a restart of your iPad will clear the problem….
To restart your router, disconnect power from the router for at least 30 seconds - then reconnect power to restart. After your router reboots (which may take several minutes), force restart your iPad:
Force restart iPad (models with the Home button)
Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.
If you continue to have difficulties, try resetting your iPad's Network settings:
Settings > General > Transfer or Reset iPad > Reset > Reset Network Settings
