I've had this problem on more than one printer, so I believe the issue is to do with the computer that I intend to scan documents to.
On two different multifunction printers (HP and Canon), I've attempted to set up scanning to a share on a Windows 7 machine.
In the printer's web UI, it gives me options to put the computer's hostname (or IP), the share folder, and a username/password.
It doesn't matter whether I use hostname or IP, the scanner cannot connect to the remote computer.
I can ping the printer from the computer. Permissions are set up for the username that I've set up.
I'm wondering if there is some sort of firewall or antivirus issue blocking the connection, but I don't even know where to start. There isn't dedicated software I'm using to scan, it's just a direct Windows SMB scan.
As far as error messages go, on one printer I got a generic "Can't Connect" error. On the one I'm currently trying to set up (Canon), I get an "Error 806", which is a credential error, but I am absolutely positive I have entered the credentials correctly.