http://sn.1w6.org/file/bobjonkman-20170106T200334-tbahl7w.html

#Spamhaus isn't actually blocking you. Your recipients are relying on Spamhaus to determine what they (your recipients) will allow into their mail server. So the fault lies with your recipients, who have chosen a third-party that mis-identifies your mail server or IP address as spam, and then your recipients compound the error by letting that third-party actually block their inbound mail instead of just tagging it. Sadly, your recipients will never realize which items the third-party is censoring, because they'll never receive those items to classify them for themselves. !SysAdmin