CSS is not loading
If your CSS is not loading this could be for multiple reasons.
The first think you need to do is go into general settings off the plugin.
And change the "Include Css Files To" - "Footer"
Most chances after saving this should help.
If this solution does not help you should start deactivating and optimising or SEO plugins which might be interfering one by one.
Once you found the conflicting plugin you should contact their support for them to give you a resolution.