DNS: cannot add alias "autoconfig.mydomain.lan" , only local ping works

[ATT1]

Hello,
I have the following problem: I cannot add an alias for my zentyal server "srv01". The alias I want is "autoconfig.mydomain.lan".
I try to add it under DNS settings - they get added - but the only one host who can ping "autoconfig.mydomain.lan" is the Zentyal server "srv01" itself. No other host in the local network can ping "autoconf.mydomain.lan".  Why ?

nslookup autoconfig
says
"non existant domain"

What can I do about it ?

[ATT1]

It's getting stranger by the day:

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. Alle Rechte vorbehalten.

C:\Users\Admin>nslookup autoconfig.mycompany.lan
Server:  srv01.myconpany.lan
Address:  192.168.0.174

Name:    srv01.myconpany.lan
Addresses:  192.168.0.174
          192.168.10.1
Aliases:  autoconfig.myconpany.lan


C:\Users\Admin>ping autoconfig.myconpany.lan
Ping-Anforderung konnte Host "autoconfig.myconpany.lan" nicht finden. Überprüfen
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