Why is it when I type something in the anime-supreme channel it says #anime-supreme Cannot send to channel?
The channel is most likely +m (moderated) meaning you need to have voice (+) status in the channel to be able to speak. There could be other network-specific modes affecting your ability to speak in the channel however - for help, ask the ops (@) of that channel by messaging them: /msg nickname messageHERE.
Regards,