This question has 2 downvotes. I know only the voters know why they think it's bad, but if you are a voter, then why is that? I think the only reason is because it lacks research, but I have provided everything I know.
My guess is because the question could be clearer.*
E.g. I only use Facebook from within a Windows browser, and some things strike me as unclear:
- if you send a message. From where/with what app?
- does the receiver really accept, or just read?
- message to a page?? Since when can you send messages to a page? Am I missing something here? You can only post to/on a page, I believe.
- What is the Facebook Page app? Do you mean the Facebook Pages Manager?
Some screenshots would have helped a lot to understand what you're asking.
* I notice many unclear questions on this SE site having downvotes without comments. My guess is there are people getting a bit fed up with dealing with unclear questions and they do not want to spend more time on those than a quick downvote.
I know only the voters know why they think it's bad
This is, unfortunately, the crux of it. I'm sorry that someone didn't leave a comment as to how it could be improved. I don't see much, if anything, wrong with the question.
The only thing that someone might take issue with (and again, I can't speak for the rationale of the voters) is that
I wonder if the admin of the page has to accept it so that the status can change to Delivered. Is that correct?
could potentially only be answerable by Facebook themselves, and therefore, this is inviting speculation about their internal policies and business logic.