[Samba] join fails: invalid server state

[Lars Hanke]

I'm launching the final phase of getting my new Samba4 AD DC productive. 
I wanted to join the first real workstation, but it failed:

# net ads join -U Administrator
Enter Administrator's password:
Failed to join domain: failed to lookup DC info for domain 
'AD.MICROSULT.DE' over rpc: Invalid server state

This issue was reported already here: 
https://lists.samba.org/archive/samba/2012-July/168212.html, but 
following the tips there neither changed any DNS info involved nor did 
the trick.

Some verified facts about my setup:

1) I have joined other systems to the AD DC.
2) If I enter a wrong password, I get a different error message, i.e. 
the server is actually contacted.
3) I can do a kinit Administrator successfully, i.e. Kerberos is running 
fine.
4) The variants of hostname [-f] [-d] [-s] report correctly.
5) Forward and backward resolution of both the AD DC and the client work 
correctly. For the client this is achieved by an entry to /etc/hosts, 
since it has not yet joined, i.e. is missing in the DNS of the AD DC.
6) The host -t SRV queries also report correctly.

What does the message "invalid server state" want to tell me?

Thanks for your help,
- lars.