What is the full form of BFN?

Excuse me, could you clarify something for me? I've encountered the abbreviation 'BFN' quite frequently in online conversations, but I'm not entirely sure what its full form stands for. Could you please enlighten me on this matter? I've searched online but found several conflicting explanations, ranging from business-related terms to more informal greetings. As a professional in the field of cryptocurrency and finance, I assume you might have a more accurate understanding of this abbreviation's origin and usage. Your input would be greatly appreciated.