Two new M80 handsets will not register with M700

I just purchased 2 new M80 handsets, to work with my M700 base station, but they will not register with the base station.  I tried updating the firmware of the base to v530b1400 and the base’s home page now shows:

Firmware Version:           IPDECT/05.30/B1400/07-Nov-2024 10:54
Firmware URL:  Firmware update server address: http://dect.snom.com
Firmware path: B355B25H355B25
Reboot: 2025-01-20 21:15:15 (3) Normal Reboot (21) Firmware Version 0530.1400
(RESET_CAUSE_WBM_NORMAL_REBOOT)
Reboot: 2025-01-20 20:45:20 (2) Forced Reboot (81) Firmware Version 0530.0010
(RESET_CAUSE_MAIN_CODE_UPDATE)

I rebooted the base, and then tried to register the new M80’s using “easy registration”, also tried using the steps shown in the manual:
Menu > connectivity > Register > Empty (first entry) > 0000 (access code) > Ok

But both M80 phones spend a long time at the “registering” screen and eventually ”registration failed”.  Is there something I need to do on the base station first?  How do I get the M80’s to register?  Your online product guide says the M80 is compatible with the M700, but my M700 (running v530b1400) doesn’t even list the M80 in the list of recognized handsets on the web page (see screen shot below).

Please advise what to do next.  (I tried to open a ticket on SNOM's Jira site, but there is just no way to open a ticket)