I am sorry to hear this is happening! We're working on getting this issue resolved but are you able to help with some details?
When you click into the details of the error do you see the message to restore your Facebook connection? First, please login to Facebook in the same browser but on another tab. Once this is complete return to the tab with Constant Contact and click to restore the connection. Did this help?
Are you the only admin on this Facebook page?
If you would like I can leave your case open to have you notified when this is resolved, just let me know!