Error during SQL Server 2012 Failover cluster installation

Dear Experts,
Need your urgent help.
I have a 2 node windows fail over cluster.
I am trying to install a SQL fail over cluster but the setup fails at the service accounts page.
I have confirmed the service account and password is valid.
There are other services on the same server that are running fine under this account.

Below is the error:

The RPC server is unavailable.
TITLE: Message Details

The SQL Server service account login or password is not valid. Use SQL Server Configuration Manager to update the service account.



Just got this fixed.
Was a DNS issue.
Append parent suffixes of the primary DNS suffix.