[Samba] krb5_kt_start_seq_get failed (Permission denied)

[Yakov Revyakin]

On a DOMAIN Linux member in log.wb_DOMAIN I can see the error message
"krb5_kt_start_seq_get failed (Permission denied)" during any attempt of
user authentication.
In result a user is authenticated successfully. But what does this message
mean?

My krb5.keytab has permissions 600 by default.
If I change its permissions to 644 the error message goes.