by AverageJoe » Mon Aug 10, 2015 12:47 am
"Unable to connect" in the WoW login screen typically means you're using an incorrect password.
"Bad credentials" on the Nostalrius website also means your password is incorrect.
If you keep logging in WoW unsuccessfully, you'll get temporarily IP banned from the server that lasts about 15 minutes. You can either try really, really hard to remember your password or wait 10 days out from your last successful login and try to reset the password to something much simpler.