Logon Faied – Authentication Failed

I am very very new to wordpress and most importantly to ADI. I need to setup ADI on my wordpress based website but I am unable to setup the Server Information Correctly I assume. Because the test tool gives me Logon Failed error but what can be the possible issues for failed Authentication?
1- Credentials are not correct?
2- DC is not valid? { it says – OK against DC connection which can be seen in the screenshot attached}
3- Base DN is empty. { My supervisor said that you can leave the Base DN address so ADI will lookup to all the Base DNs available under the DC of their organization i.e. ldap://domain.local}

Any help would be greatly appreciated