The Artwork I Inquired About Is Not Available Anymore. Why?

It may happen to receive a reply from a gallery saying that the artwork you inquired about is not available anymore. This can happen for various reasons - the artwork might have been sold to another collector or the gallery might have not updated its catalogue. 

Even if the chosen artwork is not available, you can always engage in a conversation with the gallery and ask them for other pieces or to be informed about new availabilities.