You are unable to connect your Nintendo Switch console to a wired network and receive the error code 2110-2091.
A USB LAN Adapter is required to set up a wired internet connection when using a Nintendo Switch dock without a LAN port.
A USB LAN Adapter can be connected to a Nintendo Switch Lite system using a licensed accessory.
This error code typically indicates the Nintendo Switch could detect the LAN adapter, but that it was unable to communicate with any network devices (e.g. router or modem).
This error may be due to issues related to the Ethernet cable or network devices.
Ensure the Ethernet cable is securely attached to the LAN adapter and networking device.
Both ends of the Ethernet cable should fit securely into the Ethernet ports on the LAN adapter and the router/modem. If either end of the cable does not stay secure, you may need to try a different Ethernet cable.
Power cycle your home network.
Restarting your network devices may resolve this issue if it is related to the devices being unresponsive.
Try a different port on the router.
If you are connecting to a device with multiple LAN ports, try connecting the Ethernet cable to a different port. Most routers will have at least 4 ports available for use.
Try a different Ethernet cable.
If a second Ethernet cable works, this may indicate the Ethernet cable originally used is damaged or no longer working.
Situation Not Resolved:
If you are still unable to connect, this may indicate an issue related to the network environment or networking devices being used.
If your modem and router are separate devices, attempt to connect the Ethernet cable directly to your modem. If you are able to successfully connect online, this may mean the issue is related to the router being used. In this situation you may wish see if using a different router resolves the connection issue.
If you would like further assistance with the Nintendo Switch console, please contact Nintendo Customer Service.