From WHMCS Documentation
|Update Nameservers||Update WHOIS||Get EPP Code||Register Nameservers|
|DNS Record Management||Email Forwarding||Domain Release||Domain Sync Script|
IP Registration (Registrar Error Invalid Client IP)
- In order to use the Namecheap API, you must first contact them and let them know the server IP address where you will be connecting from (the server IP address where you have WHMCS installed)
- This is part of Namecheap's security measures to prevent unauthorised users being able to submit registration requests to your account.
- You can do this by opening a ticket with Namecheap directly asking for your server IP address to be authorized for access to your account