For the past two days, I've had terrible problems with my Wii U, and nothing else (3ds, wii, PC are unaffected). I'll be using the Internet Browser, Miiverse, eShop, and even the friends list when it will suddenly give me an error code and stop working for no reason. And when I check, half of these error codes are not even recognized! Such as:
121-9998
112-1006
106-0612
102-2128
111-1006
Sometimes it will work just perfect for 5 to 10 minutes, then in the middle of a youtube video or a miiverse post it suddenly decides it doesn't want to work. I've tried restarting the Wii U and restarting the router, to no avail.