Experiencing 104-2210 error even after nimble fix? The router of your home network is blocking incoming traffic. So, from within router configuration page you need to, either, disable firewall, or create an application defining UDP port range 1024 to 65535 and assign it to Wii U.
Post
Yo gain access to router configuration page via a web browser, from a pc or laptop, typing the line 192.168.1.1 on the address bar.
Did you delete ypur shared save data?
No, I haven't touched the save files. Do you think the share folder has something to do with this error?
When I toggle between the described settings on my router I witness the different behaviour from the game. When incoming traffic is blocked I get the 104-2210 error, but when I unblock it, with the described procedure, the game plays flawlessly.