diff --git a/roles/mail/templates/postfix-out/main.cf b/roles/mail/templates/postfix-out/main.cf
index 94818820f40f2363bf37b659f85d834285706c4e..ce84039027db76b5f7ac97566844bbf7066e2801 100644
--- a/roles/mail/templates/postfix-out/main.cf
+++ b/roles/mail/templates/postfix-out/main.cf
@@ -49,7 +49,7 @@ transport_maps = ${ldap}all-recipients ${indexed}transport ${indexed}mailman_tra
 virtual_alias_maps = ${indexed}virtual ${ldap}aliases
 
 # Message size limit.
-message_size_limit = 15000000
+message_size_limit = 20971520
 
 # Concurrency tuning for "relay" and "smtp" transport.
 relay_destination_concurrency_limit = 20