Cracking kerberos

[Yara]

Hello all 
I’m trying to use hashcat to crack Kerberos pr-auth etype 18, I tried this

hashcat -19900 ‘$krb5pa$18$yara24$KTG.LOCAL$9e369416abca8ad80c4055e1286e0710de928f9b2ce0b3b88e59a17cfe7d9f5103a129dd750d130db33d99b20f37d4bc21d88518c950e7d3’ rockyou.txt

But no results have been found, I wonder why? Am I made mistake or the Kerberos has solved the cracking issue