For security purposes, when adding a domain (registered in Hostinger) to a hosting plan (purchased at Hostinger), both the domain and the hosting plan should be in the same Hostinger account.
If your domain and hosting plan are in different accounts, you will receive the “Domain is registered in another Hostinger account” error. To solve it, move your domain name to the account where your hosting plan is.
In case your domain is already on the same account, and you're still seeing this error, reach out to our Customer Success team, and we will help you out 💪