Hello, are you signing up as a patron or a demo user? Off the top of my head that sounds like a vpn issue. Are you using a vpn? You will need to turn it off only temporarily for the first login.
This FAQ video may be helpful:
https://soulcoom.itch.io/soulcoom/devlog/568459/faq-how-to-signup
There could be a couple reasons you are stuck in a loading loop, something is blocking the game from speaking to your browser or you have it open already but buried in one of your browser tabs. Other solutions: Please check to see what your default browser is set to in Windows and add a default browser. If you are using a VPN, Ad-blocker, or a antivirus firewall, you will need to make an exception or disable them for your first login.