Register ACS 5.4 Secondary to Primary problem after change hostname

[TIAGO MATIAS]

After i change the hostname from my ACS Secondary i can´t register to primary again.

The erros is :

This System Failure occurred:  ACS50RMIAPI Unable to register node. Possible cause of this exception is an invalid hostname or invalid ip address has been entered.. Your changes have not been saved.Click OK to return to the list page. 

I need reimage the box ?

[Flavio Miranda]

 Hi Tiago,

  Is it the new hostname resolvable by the DNS ? 

[TIAGO MATIAS]

Hi Flami, i will check it, this was a old hostname that we need use again.

The resolvable DNS  is mandatory?  i try register using the IP.

Thanks a Lot.

[Flavio Miranda]

Well, read that out from a Cisco Documentation:

" Prerequisites:
• The fully qualified domain name (FQDN) of the standalone node that you are going to register, for
example, ise1.cisco.com must be Domain Name System (DNS)-resolvable from the primary
Administration ISE node. Otherwise, node registration will fail. You must enter the IP addresses and
FQDNs of the ISE nodes that are part of your distributed deployment in the DNS server."