Hello! Need some help with sssd - tried to add my new machine ecologyubuntu to AD - unsuccessfully:

sudo realm join --verbose --user=administrator dc.mydomain.ru
* Resolving: _ldap._tcp.dc.mydomain.ru
* Resolving: dc.mydomain.ru
* Performing LDAP DSE lookup on: 192.168.0.10
* Successfully discovered: mydomain.ru
Password for administrator:
* Unconditionally checking packages
* Resolving required packages
* LANG=C /usr/sbin/adcli join --verbose --domain mydomain.ru --domain-realm MYDOMAIN.RU --domain-controller 192.168.0.10 --login-type user --login-user administrator --stdin-password
* Using domain name: mydomain.ru
* Calculated computer account name from fqdn: ECOLOGYUBUNTU
* Using domain realm: mydomain.ru
* Sending NetLogon ping to domain controller: 192.168.0.10
* Received NetLogon info from: dc.mydomain.ru
* Wrote out krb5.conf snippet to /var/cache/realmd/adcli-krb5-Tqn6cK/krb5.d/adcli-krb5-conf-xkL8EJ
* Authenticated as user: administrator@MYDOMAIN.RU
! Couldn't authenticate to active directory: SASL(-1): generic failure: GSSAPI Error: Unspecified GSS failure. Minor code may provide more information (Server not found in Kerberos database)
adcli: couldn't connect to mydomain.ru domain: Couldn't authenticate to active directory: SASL(-1): generic failure: GSSAPI Error: Unspecified GSS failure. Minor code may provide more information (Server not found in Kerberos database)
! Insufficient permissions to join the domain
realm: Couldn't join realm: Insufficient permissions to join the domain


When I tried this:

kinit administrator@MYDOMAIN.RU
Password for administrator@MYDOMAIN.RU:
garett@ecologyubuntu:~$ klist
Ticket cache: FILE:/tmp/krb5cc_1000
Default principal: administrator@MYDOMAIN.RU

Valid starting Expires Service principal
10/15/20 18:24:32 10/16/20 04:24:32 krbtgt/MYDOMAIN.RU@MYDOMAIN.RU
renew until 10/16/20 18:24:27

Also I disabled ipv6 but no effect. Here is /etc/hosts:

cat /etc/hosts
127.0.0.1 localhost
192.168.0.171 ecologyubuntu ecologyubuntu.mydomain.ru

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Password for administrator@mydomain.ru is 100% correct - what is wrong with my conf? Please help.