When our agent tries to CC one of our third parties, we receive "Message not delivered -Message bounced - Temporary error" from them. I inquired further and they investigated server logs and saw the following :
===email server paste===
2020-08-19 15:22:33 ProxyMatch, ProxyDeny: SMTP Classified as confirmed SPAM, pri=6, disp=Deny, policy=SMTP.IN.02-00, protocol=smtp/tcp, src_ip=3.120.181.192, src_port=60529, dst_ip=195.244.65.20, dst_port=25, src_intf=0-SoneraOut, dst_intf=105-Net65.0Mask27, rc=595, proxy_act=SMTP-Incoming.smtp, sender=bounces+1.1472028-asiakaspalvelu:liikku.freshdesk.com@emaileuc.freshdesk.com, recipients=laskutus@cash-in.fi, 1BFF-0019, geo_src=DEU; geo_dst=FIN
===end===
They whitelisted IP 3.120.181.192 (which seems to be the Freshdesk server), but the error still persists and our agents are unable to send emails.
