If you are experiencing difficulties using the DR-C225W or DR-C225W II wireless (via Wi-Fi ) on macOS 11 (Big Sur), please follow the steps listed below.
If you are connected via USB and receive this message, make sure the Wireless button on the back of the scanner is set to "OFF". By default, it is set to "ON" and you will receive this error message if trying to use the scanner via USB.