If you want to test what a player sees, start a second instance of MapTool and connect to your server as a Player. Now you'll see what that player would see because you've actually logged into the server as that particular player
I had just that setup, with the lappy set up next to the desktop as server.
I had this problem twice, once with my desktop(GM server) and lappy(player) setup, and once again with my lappy(GM server), and a friends lappy(secondary GM).
After fiddling with no avail for a while, and then in frustration posting here (hate not being able to figure it out for myself), I took one more stab at it, and without having closed MapTool, I think I may have reloaded the campaign (it's been a few days), and all worked as it should. Maybe a bug?
I have not fiddled with it since, but when I do I will give an update.
Thank you kindly for all of your help.
This being my second post on the forums, I would like to say that I am quite impressed with the community here.