[SOLVED] ImageCLASS MF644Cdw: Can print but cannot scan (MacOS 15.1)

[wilberfan]

[EDIT]  IT WAS THE VPN!  🤦‍♂️  Despite enabling local network access, the VPN app was preventing the scanner (not the printer) from communicating with the computer.  Two days and ten hours I won't get back...  But at least I have a working scanner now... 

Neither Image Capture nor the Canon Scan Utility (v1.10.17) can communicate with the scanner.  

"Cannot communicate with the scanner  Error code: 600104"
"Cannot communicate with any of the scanners. The scanners may not be connected, or may be turned off."

• I've updated the firmware and all available drivers
• I've done a factory reset on the printer
• I've deleted and re-added the printer multiple times
• I've connected to the network (successfully) with via both Wi-Fi and USB
• I am able to print without issue.
• I can retrieve printer supplies and open the 'printer page' via a web browser.
• I cannot scan from computer > Scanner nor Scanner > Computer (via the touchscreen menu)

I've run out of ideas... 

[wilberfan]

It makes no sense, but it turns out I had to install BOTH the scanner AND FAX drivers to enable my iMac to communicate with the printer/scanner--but only with the MacOS Image Capture app.  Neither MF Scan Utility nor the MF Toolbox can see the device.   🤦‍♂️

[wilberfan]

Installing the fax drivers may have been coincidental to something else that somehow made the scanner visible to Image Capture.  In attempting to get the MF utilities to work, I'm back to square one, where I can't access the scanning function at all.