This does not seem to affect all users.
The reason I think it's a cache issue is for some clearing their cache fixes it. For some using private or incognito window in browser they can posts and see the post box.
But some despite doing all this can not. How can I fix this? Its been several days now since I moved host so I cant see it being propagation, plus the site on the old host is closed anyway so they wouldnt see anything.
Any ideas welcome