I just moved servers, and everything seems to be working correctly, minus the adminCP. I can log in fine, but as soon as i click on any link, i am forced to login again. This repeats itself continuously (although stuff still goes through to the link i click, as well as updates any changes i do). It's more of a hassle than anything. And yes, i have cleared my cookies to make sure that wasn't an issue. It looks like the session id is expiring perhaps?
I suspect the issue is with your session.save_path location. That being said, please do follow up to let us know what fixed it.
Cookie sessions weren't enabled (only transient ones). After having them enable them all is good again.