rDNS/PTR record for 34.231.109.238 is "ec2-34-231-109-238.compute-1.amazonaws.com".
Some mail servers will not accept mail from IP addresses with no rDNS/PTR record or a generic PTR record.
The following are blacklist test results. Being listed with a DNSBL does not always indicate the IP address is a source of spam. Some DNSBL's criteria are based of the IP address' country or connection type. If you are listed with a DNSBL click on the link for removal criteria.