Sorry for the much delayed response, but if your still having the problem I do believe it is a common problem when one of the two plugins are out of date, or one of the commons plugins like Vault, as This plugin does not have a use for protocollib currently.
Version: 1.0.8
Amazing Plugin, Dev is very helpful and will fix bugs right away. Also releases Amazing updates with new Features and Bug fixs, I give this plugin 10/10 Stars.