Adobe Digital Editions - Connection Error Detected

I have been using Abode Digital Editions for months and last week it stopped working. I receive the error message below:

I have verified I am connected to the internet (logged in the library). I have tried uninstalling and reinstalling, it worked once as I was able to download one book, now I am unable to return it. I have tried uninstalling and reinstalling multiple times unsuccessfully. I am currently using Windows 7 with Adobe Digital Editions 3.0. I have tried installing versions 4.5 and 2.0.1 as well. Any help you can provide is appreciated.