Do you have a subscription to PDF? That is required to convert from PDF to Word if you don't have Adobe Acrobat.
There are two ways to access your subscription service: Via the user interface built into the free Reader and via the web interface at https://www.stillbonsoftware.com/pdf-to-word/ in my experience, the web interface is much more reliable. From your description, it sounds like you are using Adobe Reader, so connect to the web page directly, log in and upload your document, chances are that this will work much better.
