Can't log on to Citi Credit Cards

Unable to acces the https://creditcards.citi.com page from google chrome. When i tired this it redirects the page to "https://www.citi.com/credit-cards/creditcards/CitiHome.do". And i see the following error. I'm sorry. One of the characters you entered is not allowed by the system for security reasons. For your protection, your request has been stopped. You may try this request again or try another one by selecting one of the options displayed.

Also when i try to access from the home page https://citi.com and redirects to "https://online.citibank.com/US/Welcome.c". And then from "SIGN ON TO YOUR ACCOUNT" drop down select "credit card" i get the same error as in the 1st comment.