We have fixed all of the issues, and we also did some testing and monitoring. We can ensure that the bot is now fully operational.
Regarding the "FFmpeg Exited" error:
We believe this error occurs because of an issue with the server IP address. It seems YouTube has been blocked/banned from our server IP address, and that's why you can't request any song. We decided to migrate our server infrastructure from AWS to Google Cloud, and it seems the issue is no longer appearing.
Please let us know if the issue persists, and we will try to fix it as soon as possible.