Is the latest firmware applied to the ScanSnap?
Update the firmware of the ScanSnap to the latest version.
For details, refer to here in the ScanSnap Help.
Is connection to the Internet established via a proxy server?
Use the ScanSnap in a network environment that does not use a proxy server.
Are the ScanSnap and the mobile device connected to the same network?
Connect the ScanSnap and the mobile device to the same network.
To change the wireless access point configured for the ScanSnap so that it connects to the same network as the mobile device, refer to the here in the ScanSnap Help.
Are the ScanSnap and the mobile device connected via a direct connection?
When saving scanned images to a cloud service using ScanSnap Cloud, connect via a wireless access point.
For details, refer to How can I connect my ScanSnap to a wireless access point?.