The system sends this domain’s outgoing mail from a private IP address

I have a problem with Email Deliverability I try create a rDNS but the system says: The system sends this domain"s outgoing mail from a private IP address, "xxx.xx.xx.xxx". Reverse DNS does not work with private IP addresses because DNS does not store PTR records for them. The server is on AWS, and when I try to change IP on WHM to my Elastic IP (public IP) in AWS the whole server falls. I need this to prevent my emails from getting spam I hope someone can help me to resolve this problem.