Error: "Failed to authenticate to directory @ HOST.YOURDOMAIN.COM:389 (49, Invalid Credentials)" (4249353)

If  a username that is greater than 20 characters in length is used as the Admin User in the Defender Security Server Configuration the following error may be seen in the 'Test Connection' tab of the Defender Security Server Configuration tool.

02:26:13 Performing LDAP connectivity tests
02:26:13 Authenticating to HOST.YOURDOMAIN.COM:389 with test defender no admin (test defender no admin on )
02:26:13 Failed to authenticate to directory @ HOST.YOURDOMAIN.COM:389 (49, Invalid Credentials)

Note that the error may also indicate that the username or password is incorrect.

The username or password may be incorrect.

Also, there is a 20 character limitation on User Names.

If the Defender service account is less than 20 characters, please confirm that the credentials are entered correctly and there are no other issues with the Defender service account.  It is not locked, for example.

If the Service Account Username is more than 20 characters, reduce the length of the Service Account user name to less than 20 characters or use the truncated samaccountname.