Setup DDNS on Nighthawk R7500 Unable to complete the job, reason:

Trying to set up built in router DDNS, following the official guide (https://kb.netgear.com/23860/How-do-I-set-up-a-NETGEAR-Dynamic-DNS-account-on-my-NETGEAR-Nighthawk-router). Short summary:

I use the function in Netgear Genie/Advanced/Advanced setup/Dynamic DNS

Router Firmware Version V1.0.0.124

I set Netgear as Service provider. 

Do you have a NETGEAR DDNS or a No-IP DDNS account? - no. 

Every attempt, I receive this error message

Unable to complete the job, reason:

However, there ain't ever any reason stated. I have tried updating the firmware. I have tried different spelling and random host names. I have tried using only english alphanumerical letters. I have tried suggested solutions in these discussions:

1. https://community.netgear.com/t5/General-WiFi-Routers-Non/Issue-with-mynetgear-dns-Unable-to-complete-the-job-reason/m-p/1214183#M106353

2. https://community.netgear.com/t5/Nighthawk-Routers-with-WiFi-6-AX/Unable-to-setup-DDNS/m-p/1994361#M13882

Why can't I set up a dynamic DDNS?