E_ACT_NOT_Ready. Error getting license. License server communication problem.

I downloaded adobe digital editions on my mac after creating an account and tried to download an online textbook from my college course website. I got an error message saying "Error getting license. License server communication problem. E_ACT_NOT_READY." Per online discussions, I then tried to delete the authorization after pressing command-shift-D, and received another error message saying "unable to erase authorization. Please try again at some later time."