diff --git a/helpers/is-arbitrary.js b/helpers/is-arbitrary.js
index 2baef091c..7fcf1cd0f 100644
--- a/helpers/is-arbitrary.js
+++ b/helpers/is-arbitrary.js
@@ -7,11 +7,12 @@ const RE2 = require('re2');
 const isSANB = require('is-string-and-not-blank');
 const { fromUrl, parseDomain } = require('parse-domain');
 
-const config = require('#config');
-const env = require('#config/env');
 const SMTPError = require('#helpers/smtp-error');
 const checkSRS = require('#helpers/check-srs');
+const config = require('#config');
+const env = require('#config/env');
 const getHeaders = require('#helpers/get-headers');
+const isAutoReplyOrMailingList = require('#helpers/is-auto-reply-or-mailing-list');
 const logger = require('#helpers/logger');
 const parseHostFromDomainOrAddress = require('#helpers/parse-host-from-domain-or-address');
 const parseRootDomain = require('#helpers/parse-root-domain');
@@ -160,8 +161,11 @@ function isArbitrary(session, headers) {
         )) ||
       (session.originalFromAddress.startsWith('postmaster@') &&
         session.originalFromAddress.endsWith('.onmicrosoft.com'))) &&
-    subject &&
-    subject.startsWith('Undeliverable: ')
+    isAutoReplyOrMailingList(headers)
+    // subject &&
+    // subject.startsWith('Undeliverable: ')
+    // NOTE: there are too many edge cases with outlook since it needs translated for subject
+    // e.g. there is a subject that is "No se puede entregar: "
   )
     throw new SMTPError(
       'Due to spam from onmicrosoft.com we have implemented restrictions; see https://old.reddit.com/r/msp/comments/16n8p0j/spam_increase_from_onmicrosoftcom_addresses/ ;'