ReadyNAS 716 LDAP import error

We're trying to import Users/ Groups from our Windows Active Directory and we're getting the following error:

Error in prep join domain

Some more details from the ads.log

[21-02-10 13:08:44] 4248 rndb_account.c:2577 info: ******************ADS Import Starts*********************
[21-02-10 13:08:44] 4248 rndb_ads_utils.c:176 info: ADS CMD::ldap search open: LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedNamew
[21-02-10 13:08:51] 4248 rndb_ads_utils.c:190 error: Parse error on cmd=<LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedName> output: 
[21-02-10 13:09:01] 4248 rndb_ads_utils.c:176 info: ADS CMD::ldap search open: LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedName
[21-02-10 13:09:01] 4248 rndb_ads_utils.c:190 error: Parse error on cmd=<LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedName> output: 
[21-02-10 13:09:11] 4248 rndb_ads_utils.c:176 info: ADS CMD::ldap search open: LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedName
[21-02-10 13:09:11] 4248 rndb_ads_utils.c:190 error: Parse error on cmd=<LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedName> output: 
[21-02-10 13:09:21] 4248 rndb_ads_utils.c:176 info: ADS CMD::ldap search open: LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedName
[21-02-10 13:09:21] 4248 rndb_ads_utils.c:190 error: Parse error on cmd=<LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedName> output: 
[21-02-10 13:09:31] 4248 rndb_ads_utils.c:176 info: ADS CMD::ldap search open: LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedName
[21-02-10 13:09:31] 4248 rndb_ads_utils.c:190 error: Parse error on cmd=<LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedName> output: 
[21-02-10 13:09:41] 4248 rndb_ads_utils.c:176 info: ADS CMD::ldap search open: LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedName
[21-02-10 13:09:41] 4248 rndb_ads_utils.c:190 error: Parse error on cmd=<LANG=C net -P ads search \(objectClass=group\) sAMAccountName objectSid distinguishedName> output: 
[21-02-10 13:09:41] 4248 rndb_account.c:1413 error: Cannot open LDAP search with filter (objectClass=group). Check network.
[21-02-10 13:09:41] 4248 rndb_account.c:1563 error: _rndb_account_domain_group_import() ==> 9 (56748ms)
[21-02-10 13:09:41] 4248 rndb_account.c:2614 error: rndb_ads_account_import() ==> 1 (57005ms)
[21-02-10 13:09:41] 4248 rndb_api.c:1205 error: rndb_import_nolock() ==> 1 (57005ms)

We already tried upgrading to the newest firmware (6.10.4), reboot, reset, different AD Controllers.
Someone got a solution for this?