If you've just updated EnderDragonTweaks from an older version, the patch notes may have mentioned that the config version has also been updated.
This probably means that your current config.yml is now old and no longer fully compatible with the latest plugin version.
Use this tool to convert your old config to a new one. All your custom values will be kept.
If you're having trouble or you've found a bug, please do one of the following: