Problem with adding secondary DC

Hi all

i have intranet domain “vuctt.sk” with one DC now i will add the secondary controler but the server see only domain name “vuctt”. when i try connest to this domain server popup the message “The domain vuctt refer to vuctt.sk it is right?”and i use yes ten server say the domain vuctt.sk can not be contacted or dos not exist

(the dns is integrated with AD)

can enybody help me??
thx