We recently reviewed a sample of your API requests, emails and support tickets and found that some of you were not using the correct domains.
While undocumented domains and endpoints may respond with data, you should avoid using them as they may be disabled or changed without notice.
Our network infrastructure is also updated from time to time. These changes are required for capacity planning or load balancing, but are generally transparent to you if you use the correct API host.
To avoid problems or outages with your applications you need to ensure you are using the correct hosts (and base paths) for the Twitter API you want to use. Even if your code is working now, you should check the hosts match those listed below: