WHMCS errors with domain mapping reseller setup

I have just switched from eNOM to WHMCS for provisioning and set up the provisioning plugin. I went to switch over to WHMCS for Domain Mapping and I am getting an error

Looks like your credentials are invalid. Please, check the errors sent by WHMCS server:

Invalid IP 108.174.148.116

You can verify that this IP is my actual WPMU main site by going to it. I am not sure why it is telling me it is invalid.

I went into WHMCS and whitelisted the IP but I am still getting the error.