Registered members can't stay logged in

Hi all, I admin a site at http://www.theaustralianshepherd.net – while trying to work with a plugin, I noticed that even when I’m working in the dashboard as an admin, it says on the site I’m not logged in. To test, I tried creating a new username, logged in, and . . . it took me to the dashboard! When I go to “view site” it says “log in” again.

I have deactivated the few plugins I had and it has no effect. I can’t seem to find an answer in the archives.

Thank you.