There could be a few different reasons why your scanner is not reading the document. The first issue that you should look into is to make sure that the document is compatible with your scanner. If the document is too large or a different file type, the scanner may not be able to read it. You will also want to check to confirm that your scanner is properly connected to a power source and your computer. Make sure any necessary drivers are installed and up to date. If these three things have been confirmed, you may need to contact the manufacturer or service provider for further assistance.