I received this status message when trying to send a transactional email from my web application:
"\"JunkMail rejected - pc232-11.mailgun.net [143.55.232.11]:33092 is in an\nRBL on rbl.websitewelcome.com, see Blocked - see\nhttp://www.spamcop.net/w3m?action=checkblock&ip=143.55.232.11\""
I checked this IP Address, and it is not listed as blocked. Any ideas what the issue is?