Digital editions could not connect to the activation server ???

Hi there, I have a problem since a few days, I can't open my ACSM files using Adobe Digital Editions, because when I try to open one I've got the message "Digital Editions could not connect to the activation server. Please make sure you are connected to the Internet."

I've tried to uninstall ADE, install 3.0, unauthorize/authorize my Adobe ID, nothing works, still got the message above. 

I've got the latest version of the software (4.5.11.187303).

Any help out here please ?