There are a few things to look into. Do these in order until there is no longer an issue.
1. Install latest firmware, it is located here. The release code is WC75xxSpar.
2. Take a look at the SMB shares properties and find the username as used by the printer, it needs to match as shown, wher ein previous generations the username would typically be formatted as Domain\Username, with Xerox printers going to 2008-2012 Servers it tends to be formatted as the server shows them, which is more often user@domain as seen here.
3. Verify the port is being set as 445 and not the old 139 port from the days of servers past.
4. Uncheck the Append Device Domain option here in CWIS under Properties > Connectivity > Protocols > IP(Internet Protocol > DNS
5. Verify the time on the printer is right (Grasping at straws here, but valid on a Domain controller)
6. Curse at it and report back here that none of that worked and I should try a little harder. :-)