So after patch Thurs we had similar issues / dont know if this will help... Seems to have on our side (our IT/email guy opened a case w/NetSuite): "As mentioned, NetSuite started using the SparkPost mail server for bulk emails, being the possible cause of emails not being received by your users. What you did is added a condition to your spam filter that will allow emails coming from: Sender Hostname: sparkpostmail.comemail address"