Community threads on the Miele Reddit Forum show that this error sometimes stems directly from server-side outages at Miele. If you have tried the steps above and still fail, wait 24 hours and try again.
To minimize the need for future fixes, a specific preventative maintenance routine is required for the W3717. One unique aspect of Miele top-loaders and washer-dryers of this era is the "Suds Cooled" issue. If the machine is used exclusively for cold washes, residue can build up in the miele 3717 fix