Wont publish to FB if not logged in

If I log into facebook then login to our website and publish a new post, it is published to our Facebook page as required.

If I'm not logged into facebook or one of the other authors posts a new post, we get an error message saying "Publishing on Facebook Failed".

Should I have to be logged into facebook for the post to be published? I can't give out the facebook login details to all of the other website authors.

I have granted entended permissions within the Utilmate Facebook settings and have checked the boxes for Allow auto posting new posts and Do not allow individual posts to Facebook to facebook.