users keep getting logged out

I have a number of pages restricted to Owner or Admin roles.
The message that they need to be logged in to view to contents works.
The login works and the content becomes visible.
However when clicking to other restricted pages ( Same role(s) )
sometimes triggers the message again that they need to be logged in to view….even though they are logged in!
Then when they try to login they get message that they are already logged in.

Any Idea why they are getting bumped out like that?

The page I need help with: [log in to see the link]