Kadmin: Client not found

I'm attempting to join ubuntu 16.04 LTS to a windows AD. My goal is for this client machine to be able to log in with the Windows AD username and be able to access the Windows shares.

I started by following these guides

I completed the Kerberos installation and am able to get the ticket with kinit.

$ klist
Ticket cache: FILE:/tmp/krb5cc_1000
Default principal:
Valid starting Expires Service principal
07/14/2017 15:08:25 07/15/2017 01:08:25 krbtgt/
renew until 07/15/2017 15:06:23

I went back to the Samba/Kerberos guide to create the principle for the samba service but I am unable to use the kadmin command. I get the following error:

$ kadmin -p administrator/admin
Authenticating as principal administrator/admin with password.
kadmin: Client not found in Kerberos database while initializing kadmin interface

How come I can get the ticket with kinit yet I'm not able to use the kadmin command?

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