Whitelisiting in Mendix Private Cloud

Hi guys, I have a Mendix environment which is deployed to a AWS private instance with K8. As we wanted to restrict the access to the application we have whitelisted a range of IPs. But post that external systems are not able to consume our REST Services. It is throw with the below error : 405Method not allowed '/rest/MyRuleBookService/v1/RuleBook/CreateAlertRuleBook'. ---- Error Message: Or sometimes It give "Path not found" The tricky part the same Rest service is working fine we hit it from Postman The external systems IP has been whitelisted. Any solution on how to resolve it.