If you are receiving a blank output, this generally occurs with a scanned file. For one reason or another, the program does not detect that the PDF is a scan with certain documents, in which case the OCR engine is not turned on and will not perform the necessary conversion type. When this occurs, we must manually turn the OCR engine on. Please try the following
Select "Edit" ---> OCR Options ---> Select "Perform image based conversion"
This article refers to Able2Doc Professional and Able2Extract Professional.