The failure is because there are too many simultaneous connections to the share, it would only happen if you do many scans in a short period of time to the share. The max concurrent logins to a share is 20 in Windows.
So you can try maxing the connections to 20 on the share, or switch to FTP that does not have the issue as seen here in SMB.
I have a Xerox 5335 - and it usually scans fine. But for the last few months, it has been acting up. It will scan fine for a few hours and then abruptly stop. I receive error 027-529 and the dreaded tones of death.
I have looked up solutions online, but none seem germane.
Currently, I am rebooting the server computer and the printer, and that fixes it for a few hours.
What do I do so I don't have to continue to do this.