Whatever bug is causing your website to loop people to "too many attempts 503" is causing people to be locked for suspicious activity. Simply unnacceptable.
I'm terrified to mess with my account settings as your system apparently has a loop of red flags that locks customers out when they try to access their own account information. Since the account on which I pre-ordered HotS was only just made, I can't use SMS protect or an authenticator to prove I'm legitimate, and even on this account I still keep getting looped back to ol' 503 503 503 503.
Would appreciate a blue response on this.
TL;DR Battle.net's autolock security feature (Error 503) creates a false red flag any time you try to access account settings, on any browser other than IE8.