Custom domain already in use but not attached to any of my accounts

I looked up the domain name, and it seems that the domain was added to another hosting account on our platform on the day it was registered. Did you perhaps sign up with another email address or Google/GitHub account? Please check your other email accounts for any messages from us. If you’re having trouble finding it, you can request a password reset based on the domain name. You won’t see the email address, but a password reset email will be sent to it, so you can just check your email accounts and see which one has the email.