I can reproduce your error. You created a paradox.
client max protocol = NT1
Samba disables NT1 on the server side of your install yet you specify the maximum protocol the client can use to NT1. Ain't gonna happen.
I'm almost certain you meant to add this in smb.conf:
client min protocol = NT1
If I do that and restart smbd:
sudo service smbd restart I can create the share without the error message.