Hello from my new account at sh.itjust.works. I just created this, you can check my profile. I used a temp email: temp-mail[dot]org
After you sign up, you can change the email to some random invalid email so your account is safe from getting hijacked via password reset through email. Changing email doesn’t require re-verification as far as I can tell.
Perhaps your IP got flagged for some reason. Are you using a VPN or Tor? Those may trigger some spam filters. Is your network a public one? (Eg: University, Hospital, Workplace, etc.)