I submitted a question, but it was rejected: “Sorry, new users can only mention 2 users in a post.”
My post mentioned no other users. It did reproduce a portion of a .bib file with multiple null characters (^@).
Is that seen as multiple users?
This might be the problem, yes.
Please try putting the excerpt of your bib file as “preformatted text” (by intending it 4 spaces manually or by hitting the </> button here in the editor.