Please check wether your firewall blocks any of these ports: 443, 2195, 2197, and 5223. These are the ports Apple communicates with the MDM server over. Any of these being inaccessible is usually the cause of your error.
Try doing an ICANN lookup and take the contact info you get from that and contact Apple. This DNS entry was changed on 12/15/21, and it looks like someone messed up to me...
I was having the exact same problem, however I tried it today and it worked for a regular individual (person) subscription, and also a Device only subscription in Business Essentials. Maybe they fixed that DNS entry, but it worked for me today.
I'm having this same problem. I deleted my Apple Business Essentials subscription, and then tried again, and it somehow worked on one machine. The other machine is still having the same problem installing the profile "response is not 200." Has anyone else had any success fixing this error?