iDRAC 9 - AD Auth logins succeed and just keep you on the login page

We just got our first 14G PowerEdge server, so this is the first iDRAC 9 I have worked on.

I am having a problem using the Web UI when logging in with AD accounts.

At the login page, where directed to "Type the User Name and Password and click Log In", I enter my user name and password, and select the domain.  When I click the Login button it says "Welcome, @ ! Please wait verifying credentials ..." and eventually stops, staying on the login page where it once again says "Type the User Name and Password and click Log In."

Logging in with a local account works, and when I check the Lifecycle Log it shows "Successfully logged in using @ , from and GUI."

So I tried my AD credentials from another web browser over and over...... until it told me The maximum number of user sessions is reached.  Looking at the sessions from where I was still logged in as root I see each of these login attempts that just kept me at the login page was showing as a separate valid user session.

I *am* able to use racadm with my AD credentials just fine.

I updated the iDRAC firmware (from 3.00.00.00 to the latest available, 3.02.00.01) with no change in behaviour.

I have tried multiple web browsers on three different computers... all with the same results.  If I login with my AD account it keeps me on the login page.

I know my config is correct, because I followed the same procedures I have been using for years.... using the racadm config command to apply the desired config from a cfg file, and because racadm works just fine with ad accounts.

Has anyone seen this or a similar issue?  Any suggestions on how to fix it?