I'm trying to use iRedMail with Active Directory for authentication. I have followed the instructions from the wiki but I have a problem with dovecot. When I try to verify ldap query with AD in dovecot it fails and in log I get
auth(default): Error: LDAP: binding failed (dn vmail): Invalid credentials, 80090308: LdapErr: DSID-0C090334, comment: AcceptSecurityContext error, data 52e, vece
All previous tests mentioned in the guide succeeded without any errors. Thank you in advance for any help.

Also, if needed, here is my dovecot-ldap.conf:

hosts           = 192.168.0.6:389
ldap_version    = 3
auth_bind       = yes
dn              = vmail
dnpass          = password
base            = cn=Users,dc=mydomain,dc=com
scope           = subtree
deref           = never
user_filter     = (&(userPrincipalName=%u)(objectClass=person)(!(userAccountControl=514)))
pass_filter     = (&(userPrincipalName=%u)(objectClass=person)(!(userAccountControl=514)))
pass_attrs      = userPassword=password
default_pass_scheme = CRYPT
user_attrs      = =home=/var/vmail/vmail1/%Ld/%Ln/Maildir/,=mail=maildir:/var/vmail/vmail1/%Ld/%Ln/Maildir/