Seems kinit is particular:
I had similar problems. I figured out that krb5.conf requires the realm names to be in upper case. I have converted the domain names (wherever it appears in krb5.conf) to uppercase.
[root@LinuxLS logicalfuzz]# kinit firstname.lastname@example.org
Password for email@example.com:
kinit(v5): KDC reply did not match expectations while getting initial credentials
[root@LinuxLS logicalfuzz]# kinit myaccount@CORP.EXAMPLE.COM
Password for myaccount@CORP.EXAMPLE.COM: