WotLK Cannot login to client?

[Menegroth]

I've been playing this game for a while and haven't had an issue logging in before. I played last night and went to play after work today.

When I try to login, it says my username or password could be incorrect. I even went on this website to change my password and it still won't let me in the client? Any reasons to why? And yes I do have Two-Way Authentication activated.

[Thorbjorn]

Can you be more specific on what the client tells you?

[NotYagers3]

I had the same exact problem, the client tell you "Connecting...." then gives you a message like you don't have any internet at all, been dealing with this all fricken day, IDK why, IDK how, but what I just did that worked was I reset everything in the WTF folder..... Moved my WoW folder to my desktop... Then heres the real kicker, Don't use your high dollar router even tho it worked marvelously whist you were playing this server, eliminate the router and connect directly to the POS modem the ISP gave you. I use my router the error returns, I connect just to my modem works fine.
Everything has been working fine through my router even this until today when we had a power outage, using my router everything works great except warmane, connect straight to the modem and it works fine, makes absolutely no sense, but hope this helped you.
Well your problem might be a little different, but i remember you posted on my thread saying you were having the same problem. Try that and doublecheck that your config in the WoWWTF folder matches the realmlist.wtf in the main WoW folder as well, for some reason the set realmlist line kept changing between the two files until i successfully logged in, edit and save them both, keep them open while you run the game, then after you successfully log in you should be good.