AD user Authentication in FX2s Chassis

HI,

I am having an FX2s Chassis. I am trying to bind FX2s Chassis with AD using Standard schema. there is no certificate configured in the environment. BUt i am getting an error while trying to test configuration. The test results are listed below.

Test Results
[check]: (system) Verify needed system resources: PASSED
[check]: (setup) Validate AD configuration: PASSED
INFO - (setup) Using standard schema
INFO - (setup) SSL certificate check disabled -- skipping check
[check]: (dns) Acquire LDAP and GC SRV records: PASSED
[check]: (authen) Acquire user privileges: FAILED
ERROR - (authen) AD INVALID CREDENTIAL 0x00006007
RESULT - Unable to acquire user privileges
TEST FAILED

The Firmware version of FX2s Chassis is 2.20.  Has any one faced this?