My twitch bot on my computer is completely fine but on someone elses computer the messages are not posted in chat. However, the bot’s messages are being kept in the message logs (the ones accessible with /user) The bot is a moderator in the chat, and no other accounts from the same IP address are banned in both cases.
Source code for the bot:
EDIT: The bot is in chat both times (the bot is connected to IRC in both cases), and the OAuth tokens were double checked in the faulty case.