Commented Unassigned: Unable to publish in reply to [2554]

I had the above mentioned working before and all of a sudden it has stopped. My code for replying to the tweet is as follows:

var newTweet = Tweet.CreateTweet(message);
var result = newTweet.PublishInReplyTo(tweetId);

The result is returned as false. Is there a way to figure out why?
Comments: ** Comment from web user: linvi **

Well, I cannot really help you with this. I think the best information you can get is from the Twitter Support.
But please describe what your application is doing, what calls you make in bulk, the stream you use, etc...

Cheers,
Linvi