18.211.132.41
ec2-18-211-132-41.compute-1.amazonaws.com
52.203.109.187
ec2-52-203-109-187.compute-1.amazonaws.com
54.160.94.104
ec2-54-160-94-104.compute-1.amazonaws.com

mailstream-east.mxrecord.io.
mailstream-west.mxrecord.io.