I cannot get your plugin to work. I have verified my static IP with my hosting provider. I have given that IP address to Enom. In addition, Enom also asked for the IP address of the workstation I am using - which they also added to their whitelist. They have verified that my IP address is whitelisted on their end.
Yet, the plugin/API still gives back a "User not permitted for this IP address" error.
Enom support says something is wrong with your plugin and how it is using their API. They say there is nothing more they can do. I have talked to them via phone 3 times so far to try to fix this.