We have reason to believe that Bitly account credentials have been compromised. We have no indication at this time that any accounts have been accessed without permission. If you have already followed the steps to secure your account, you do not need to do so again. Change your API key and OAuth token, reset your password, and reconnect your Facebook and Twitter accounts. Disconnect and reconnect any applications that use Bitly. If youre experiencing any trouble with the Bitly iPhone app, please update to the latest version found here.”]
Source: https://bitly.com/blog/urgent-security-update-regarding-your-bitly-account/