This riddle is usually sent via Facebook and is worded “So what do you open first to reply?”. This makes the answer ‘Messenger. level 2. dj_spanmaster. 8 points · 11 months ago. While this may be the answer, I would argue that there is nothing in the clue to indicate context vs metacontext. In the context of the riddle, this is illogical.
https://www.reddit.com/r/riddles/comments/a2qfsn/riddle_help/