That message sounds like you haven't granted permission for publishing to your company page. It's also possible that permission expired. You should try to authenticate again with the user that is the owner of the LinkedIn page to ensure the permissions have been granted.
With that said, I need to let you know that LinkedIn is removing the ability to post to pages on May 1st for most users. The only applications that will be able to post to company pages are those that are in the
LinkedIn Marketing Developer Program
.
That change is part of their migration to a new API. We're working on an updated version of JFBConnect that will support the new LinkedIn API. We'll still have the support for posting to Company Pages, but we think most users will be unable to use that feature going forward as the Marketing Developer Program for LinkedIn is not approved for most applications.
I hope that helps,
Alex