In sm.log there are 2 rows describe AD error:
6956( 8008) 12/08/2016 16:54:35 RTE D |OpenLDAP| res_errno: 49, res_error: <80090308: LdapErr: DSID-0C0903A8, comment: AcceptSecurityContext error, data 52e, v1db1>, res_matched: <>
6956( 8008) 12/08/2016 16:54:35 RTE I LDAP: SASL BIND to server ldap://<domain_name>:389 for CN=falcon,OU=**,DC=**,DC=**,DC=**returned 49 (Invalid credentials)
This error is due to – ERROR_LOGON_FAILURE (Logon failure: unknown user name or bad password.).
Returns when username is valid but password/credential is invalid. Will prevent most other errors from being displayed as noted.
Check if username and password is correct and try again.