If you get a failed to connect error while using Vlingo to update your Twitter status, this generally indicates that the Twitter service itself is unavailable at the current time. When Twitter's servers are unavailable, you won't be able to update your status using Vlingo or by sending an SMS directly. Wait and try again later.
Twitter is a service of Twitter, Inc., which is unrelated to Vlingo. You can contact Twitter at www.twitter.com.