SMB won't connect with NEW users

[Bob Zelin]

this one is crazy.
Perfectly working TVS-EC1680U. Before I describe the problem, I updated the firmware to QTS 5.0.0.1932, to see if a fresh load of new firmware would fix this problem. It did not.

Connecting from a Mac computer. I can connect with AFP, no problem. I can connect with EXISTING USERS with SMB, no problem.
If I create a NEW USER, and assign them permissions to a shared folder - I can connect with AFP without issue. But I cannot connect with SMB.
If I use the SAME computer, and log in as the admin, and then GO> Connect To Server> smb://192.168.2.3
I can connect without issue. But when it asks me to enter the name and password to connect with the NEW user, it won't connect (but it WILL connect with AFP).

So it's not like the SMB service is not working - because I can log in with SMB if I use an old user, or the admin user.

Any ideas ?
Bob

[dolbyman]

Have you checked that there is no user conflicts in the stored credentials ?

I have no mac but according to google it's in

KeychainAccess>Passwords