Assuming it’s working normally (the bot)
sure, since you said it’s in use on a few channels, I assumed it’s always sending (not with days between)
If you are not consumgings IRCv3 TAGS and COMMANDS caps enable those and read the responses backs.
Sounds like a number of possbilities or it’s not meeting the verification requirements of the channels it’s trying and failing to send to.
That could be email, phone, or plain old not following the channel.