Sorry for the issues. Is the domain new to you? It does have some history of using cloudflare and I suspect you’re getting the error due to an older past due invoice. Here is the history, https://securitytrails.com/domain/aiinsidertips.com/history/ns
whois shows the domain using cf nameservers, but the nameservers should not be changed to cloudflare until after it is added, at the moment it’s pending in the account you are using here due to the error.
You should contact the registrar, hostinger and have them revert the nameservers to their default. Next, you’ll need to follow these directions here, Billing, Plans & Subscription Questions to open a billing ticket with Support as the Community cannot see your account nor assist with account, billing and registrar issues.