Developers ban CIS IP? Or an error in the registration process?

Question

Computer networks

www.psyonix.com/forum
When trying to register from a laptop / tablet from a personal IP address, it says:
"Your IP XXXX has been blocked because it is blacklisted. For details please see www.stopforumspam.com."
This IP is clean, which was confirmed by the site staff:
www.stopforumspam.com/forum/viewtopic.php?id=6790
I tried it from the mobile Internet - the same.
I asked a friend from Ukraine (I'm from Russia-Samara) to try to register - the same problem.
Managed to register through VPN Sweden.