The problem is that it’s what I’m actually doing with the second code I shared. The event.getSocket() is the same socket created by Twitch when making the POST request to my Callback server, and the getOutputStream the output channel it’s creating. I try on the next three lines to use the output channel, write there the challenge I obtained from the request made by Twitch and I flush it, but doesn’t seem to be valid, and keeps sending me pending verifications.