This suggests you are not logging all responses from the server.
And your bot doesn’t meet on of the criteria for being able to send a message.
Or your login token doesn’t have sufficent scopes applied to it.
Check your token has chat:edit - Scopes list Authentication | Twitch Developers or use validate endpoint: Authentication | Twitch Developers
Check that your code is logging/outputting any NOTICE or USERNOTICE payloads for error reports.
This could be your bot doesn’t follow the target channel, or the bot doesn’t meet the verification requirements for the target channel.
These can be “bypassed” by giving the account the moderator role in the target channel.