As of January 15, 2017, older versions of Adobe Reader (i.e. Reader 10 and Reader 11 versions) will no longer support Export PDF and Create PDF capabilities. When attempting to execute a conversion, the following message will be returned: "An error occurred while signing in."
In order to continue to access these services through Reader, follow the instructions outlined here to get the latest version, Adobe Reader DC.
Adobe Reader DC offers added benefits over older Reader versions - you can access your PDFs wherever you are, in the office, at home and on the go. Use the “Save to Document Cloud” functionality in Acrobat or Reader to save any file to Document Cloud to make it available across devices. Files you save to Document Cloud this way will be shown in the Recent Files list in Acrobat or Reader across all signed-in devices. And the Export PDF and Create PDF tools are easier than ever to find in the Reader Tools panel.