Kerberos Authorization failed

Hi,

I use kerberos for proxy authentication. For most users it runs as expected. But I have two problems.

1. One user isn't able to authenticate. He always get the message "Authorization failed".

klist shows me as normal:

Client: xxxxx @ xxxxx.xxxx.xxx         Server: HTTP/xxxxxxxxxxxx.xxxxx.xxxx.xxx @ xxxxx.xxxx.xxx         KerbTicket (Verschlüsselungstyp): RSADSI RC4-HMAC(NT)         Ticketkennzeichen 0x40a10000 -> forwardable renewable pre_authent name_canonicalize         Startzeit: 5/29/2018 15:06:57 (lokal)         Endzeit:   5/30/2018 0:21:23 (lokal)         Erneuerungszeit: 6/5/2018 14:21:23 (lokal)         Sitzungsschlüsseltyp: RSADSI RC4-HMAC(NT)         Cachekennzeichen: 0         KDC aufgerufen: xxx.xxxxx.xxxx.xxx

Is there a possibility to resolve the issue? Otherwise I'll create a new account in the active directory.

2. Many many events "User failed in Authorization" in Fortianalyzer

I see many events "User failed in Authorization" in Fortianalyzer. They are not from users but from computer accounts. For example PC1$@xxxx.xxx.xxx. What's the reason?

Kind regards,

Janeck