If a "Failed to access ScanSnap Cloud." message is displayed on the touch panel of the ScanSnap, update the firmware of the ScanSnap.
For details, refer to here in the ScanSnap Help.
If the problem still persists even though you have updated the firmware of the ScanSnap, refer to [Windows/macOS] The ScanSnap is not connected to the network (when using ScanSnap Cloud) to take measures accordingly.