I receive an Error message when I am trying to authorize the computer o I can read an e-book in adobe digital

This is the message I receive 

code:E_adept_request_expired http://adeactivate.adobe.com/adept/activate 2014-08-23T13:32:50-07:00%20(1408825970000)%20before%202014-08-23T14:01:55-07:00%20(1408827715504)

Digital Editions encountered an error on the activation server