diff --git a/roles/mail/templates/postfix-out/transport_out.pcre b/roles/mail/templates/postfix-out/transport_out.pcre
index 167a19a5c00435f802d7281a4bf498e12b1e8b7c..ffb20529db79cc36e2ab2221d39139fb30a55b53 100644
--- a/roles/mail/templates/postfix-out/transport_out.pcre
+++ b/roles/mail/templates/postfix-out/transport_out.pcre
@@ -2,5 +2,5 @@
 # smtp transport.
 /(yahoo|hotmail|live|outlook)(\.[a-z]{2,3}){1,2}$/ smtp-lowpri:
 {% for pattern in postfix_low_priority_domains | default([]) %}
-/{{ pattern }}/ smtp-lowpri:
+/{{ pattern | regex_escape }}/ smtp-lowpri:
 {% endfor %}