I can confirm that below config works against samba 4.5.10 server. But it also work if we comment out the “client max protocol = SMB3” I am not sure what advantages it has to limit the max protocol.
[global]
preferred master = no
local master = no
domain master = no
client lanman auth = yes
lanman auth = yes
socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65536 SO_SNDBUF=65536
lock directory = /home/osmc/.smb/
client use spnego = no
client use spnego principal = no
client ntlmv2 auth = yes
name resolve order = bcast host
client min protocol = SMB2
client max protocol = SMB3