KnoxSSO support in Hue

Hello!
I want to use KnoxSSO to authentificate users in Hue.
I have Kerberized hadoop cluster.
But I faced with the problem:
When I try to authenticate my user through Knox - I could see just Hue login page.
The only error I see in DEBUG logs:

[20/May/2022 23:12:20 +0300] middleware   INFO     Redirecting to login page: /?doAs=myuser
[20/May/2022 23:12:20 +0300] access       INFO     10.216.7.253 -anon- - "GET / HTTP/1.1" - (mem: 138mb)-- login redirection
[20/May/2022 23:12:20 +0300] access       INFO     10.216.7.253 -anon- - "GET / HTTP/1.1" returned in 3ms 302 0 (mem: 138mb)
10.219.91.53 - - [20/May/2022:23:12:20 +0300] "GET /?doAs=myuser HTTP/1.1" 401 16 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:100.0) Gecko/20100101 Firefox/100.0"
[20/May/2022 23:12:20 +0300] middleware   ERROR    Unexpected error when authenticating against KDC
Traceback (most recent call last):
 File "/usr/share/hue/desktop/core/src/desktop/middleware.py", line 705, in process_request
   result, context = kerberos.authGSSServerInit('HTTP')
kerberos.GSSError: (('Unspecified GSS failure.  Minor code may provide more information', 851968), ("Key table file '/etc/krb5.keytab' not found", 2))
[20/May/2022 23:12:20 +0300] middleware   INFO     Redirecting to login page: /?doAs=myuser

But when I change
backend=desktop.auth.backend.KnoxSpnegoDjangoBackend
to
backend=desktop.auth.backend.AllowFirstUserDjangoBackend
I could access Hue interface and browse HDFS file system.

Could you help me to make KnoxSSO work with Hue?

Resolved this with setting up environment variable:
KRB5_KTNAME=/etc/security/keytabs/spnego.service.keytab