Some clients of us are blocking our mails coming to them.
ProofPoint told them that :
"We're seeing the email coming from an IP of 126.96.36.199. Although 188.8.131.52 resolves to something within the radio-ip.com domain, it's not listed in their SPF or MX record."My incoming emails goes through Zerospam system and my outgoing emails goes directly to the recipient email system.
What should I put in place so that it is all in good order?