[Samba] Failed to join domain: failed to find DC for administrator at XYZ

[Yanni]

Hi Rowland

I deleted the "domain" line from /etc/resolv.conf.

Sorry I didn't quite understand what you really meant about the last 
line in  /etc/hosts
The last line in "/etc/hosts"
192.21.35.5 testserver1 testserver1.testad.bio.ucl.ac.uk is the Win-AD. 
Samba machine does not get its IP from DHCP so I did not remove that line.

Removed 127.0.0.1 DNS from Win-AD, then restarted samba and tried to 
join it again to the AD domain but I get the very similar error below:

net ads join -U administrator at TESTAD.BIO.UCL.AC.UK
Failed to join domain: failed to lookup DC info for domain 
'TESTAD.BIO.UCL.AC.UK' over rpc: Undetermined error

So at the moment this is how my config files look like: 
pastebin.com/XGD9zy2W

Could you please have a look if you the time to do so.

Thanks a lot