You are unable to sign into your Nintendo Account on Nintendo Switch and receive the error code 2124-8028.
This error code indicates there was an error when signing in to your Nintendo Account, such as when performing actions like starting the Nintendo eShop.
While this error code is related to Nintendo Accounts on Nintendo Switch, it is likely this is due a poor network environment, such as a network with a weak wireless strength or slow Internet speeds.
Move the Nintendo Switch console closer to the wireless router.
If possible, place the Nintendo Switch within 10 to 15 feet of the wireless router to improve the signal strength during troubleshooting.
It may be helpful to remove the Nintendo Switch console from the Nintendo Switch dock while troubleshooting, and then return the console when troubleshooting is complete.
Power cycle your home network.
Restarting your network devices may resolve this issue if it is related to the devices being unresponsive.
Move any metal objects or electronic devices away from your Nintendo Switch console and wireless router.
Metal objects and electronic devices may interfere with wireless signals. If you have any of these, such as filing cabinets, speakers, power strips, glass, or cordless phones, next to your console or wireless router, move them away.
If supported by your router, connect to a different wireless band. Many routers support both the 2.4Ghz and 5Ghz frequency bands. If your router supports both, set up a new Internet connection and connect to the band you are not currently connecting to. Many routers will have default SSID names that label whether the connection is 2.4Ghz or 5Ghz, but if you're not sure, you can review this information within your router's settings.
Situation Not Resolved:
If this issue persists, it may just indicate a temporary issue with your Internet service. Wait a while and try again later.
If you would like further assistance with the Nintendo Switch console, please contact Nintendo Customer Service.