This is a small office with 4 Windows 10 computers and a Xerox Workcentre 7830 Printer, Scanner, Fax machine.
The office practice is to scan documents into a "scans" file folder on each computer.
The address book lists each computer.
They are generally addressed via their fixed IP address on the LAN subnet.
As nearly as I can tell, the Sharing, Security settings for the folders are the same.
The file sharing SMB IN and OUT port 443 are the same on the Windows firewalls.
File sharing and security is generally for Everyone and Guest. I don't think that Everyone would help but it's there.
Networking is set to not require passwords for file shares.
Some computers have been having intermittent scan results.
Some scans (or today, almost all scans) are failing on 3 out of the 4 computers.
One computer continues to work.
There is nothing much to say about the physical network - all the computers are homed into a single router as is the printer.
The printer controls and tools seem to be failry simple and I haven't found any logs to examine, etc.
What should I be using and looking for to fix this?