I can't scann a document

I have this all in one (printer, copier and scanner) conected to the computer, i'd just copy some stufs but right now I'm trying to scann the copys to the computer and I can't but I don't know why, I'd already go to menu select the option Scan and click menu agan and it appears to be saved but when i click the start button it only seems to start coping the document instead of scaning it.