From LedHed's Wiki
Overview
By default Kerberos authentication will fail when accessing a server using a DNS Alias / CNAME.
Solution
Create an alias for the host in Active Directory using the 'netdom' command:
netdom computername <FQDN> /Add:<ALIAS>
Example:
Server's FQDN = FileServer-01.domain.tld
CNAME/Alias = FS1.domain.tld
netdom computername FileServer-01.domain.tld /Add:FS1.domain.tld