Any misspelling in the krb5.conf file might cause a failure when you add a host.
When you are adding a host, the Kerberos authentication is unable to reach a Key Distribution Center (KDC) for yourrealm.
Cannot get kdc for realm YOURREALM.COM
realms sections in the krb5.conf file might be misspelled.
Verify that the
realms sections in your krb5.conf file are spelled correctly.