Why am I getting the oops message about DRM when it has worked fine for the last month

Purchased a Kobo Glo in the last month to replace a Sony. After a major learning curve got it to work on my computer and tablet. I have borrowed several books from library without a problem but now everything I borrow comes up with a message  about DRM rights and Adobe ID not authorized. It wants me to sign in with Adobe ID but I don't know where to do this. It has worked fine up to now. I did as someone suggested in  a forum and signed out and resigned in to my Kobo account. That seemed to take forever with no change . Since there is no human you can talk to on a help line I am trying this.