You only need to set the sasl wrapping to plain when talking to windows ad. With a samba/ubuntu AD, Try removing that setting entirely from smb.conf. The default value ("sign") should be enough in that case.
You only need to set the sasl wrapping to plain when talking to windows ad. With a samba/ubuntu AD, Try removing that setting entirely from smb.conf. The default value ("sign") should be enough in that case.