Samba Share user/password error after update

I had exactly the same problem. Adding

client use spnego = no

to the [global] section of /etc/samba/smb.conf solved the problem in my case. Apparently the default value changed to "yes" after the update to v.4.3.8, so I needed to explicitly set it.

See the online manpage for reference.

I first added the line client use spnego = no at the end of file /etc/samba/smb.conf, but it did not work. After I placed the line near the beginning of the file, the network drives worked.