WAC730 can't change default PW & not found by WC7500

Hi, I am trying to add a WAC730 as a controlled AP of my WC7500.  The WC currently controls 4 WAC720 and 1 WAC730.  I have plenty of licenses left and I am swapping out one of the 720's for the 730.  All the currently-working APs were discovered and added easily.  This WAC730 is giving me much trouble.

I factory reset the WAC730, however the WC7500 will not discover it.  The good news is it is getting a DHCP IP.  When I access the web UI it redirects to an HTTPS connection which causes a browser warning, then I can log in with default "admin/password".  However it immediately requires me to set a strong password, which I do, but then when I try to log in with the new password it fails.  I can log in again with default "admin/password" and the cycle repeats so I am effectively locked out the the AP.  If I try to SSH into the WAC730, I get "connection refused".  So it is not saving the new password.  The password is at least 8 upper and lower case letters and numbers (no special characters for now).

How can I 1) get the WC7500 to take control of this AP and 2) successfully change the PW on this AP?

The WAC730 is running fw ver: 3.9.1.13 and the WC7500 is at fw ver: 6.5.3.2

Thank you for any help.

Russell