Scanner can't access a shared folder on 10.11.5

I shared out a folder on OSX 10.11.5. The permissions are correct. I can access the share from a Windows machine (it asks for credentials and is REALLY slow to show files) but when I try to scan a document to the share it errors out every time. This worked until recently. I am 100% sure the credentials on the scanner are correct.

Just so there's no confusion I set up an account on my networked scanner (which is on the same subnet) with the same credentials as those of a user on the OSX machine. The share is visible and writable from a Windows machine. When I scan from the scanner (A Konika Minolta Bizhub) it says "Error: cannot connect to server." This is not a login/permissions issue as when I change the credentials I get a different error message.

Any ideas?

iMac, OS X El Capitan (10.11.5)

Posted on Jun 8, 2016 8:29 PM

Jun 13, 2016 6:45 AM in response to AFUser

As per another reply it would help to know what previous OS X version you were using that did work. Things to try are as follows.

Get your Konica-Minolta support rep to upgrade the firmware in your BizHub to the current, this will address some issues although this may not be your particular problem
Check your settings in your BizHub under Network -> SMB Setting -> Client Setting and make sure it is set to NTLM v2
The file path as entered on the BizHub should be in Windows format i.e. \ShareName not Mac/Unix format i.e. /Sharename
If the problem only occurred after upgrading to El Capitan 10.11.5 then it maybe due to a new change in 10.11.5 which enforced signing of SMB packets, this can be turned back off on the Mac server by doing the following command.

sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.smb.server SigningRequired false