Don't get my PC authorized - error message: Activation server error: E_ADEPT_REQUEST_EXPIRED. I have uninstalled and re-installed Adobe Digital Edition - same problem

Yesterday I have down loaded Adobe Digital Edition in order to read an ebook I have purchased. When I want to authorize my PC it gives me an error message: E_ADEPT_REQUEST_EXPIRED. I have un-installed Adobe Digital Edition and re-installed, but the problem stays the same.What ells is there I can do to get this problem resolved?