diff --git a/roles/mail/templates/postfix-out/main.cf b/roles/mail/templates/postfix-out/main.cf
index 10c0f82b3c651108ef84e200f53218eaa634bcbe..867769dc03834d21d9d9bb782e344482c882ea34 100644
--- a/roles/mail/templates/postfix-out/main.cf
+++ b/roles/mail/templates/postfix-out/main.cf
@@ -54,9 +54,11 @@ virtual_alias_maps = ${indexed}virtual ${ldap}aliases
 # Concurrency tuning for "relay" and "smtp" transport.
 relay_destination_concurrency_limit = 20
 default_destination_concurrency_limit = 20
-smtp-lowpri_destination_recipient_limit = 1
+smtp-lowpri_destination_recipient_limit = 10
 smtp-lowpri_destination_concurrency_limit = 2
-smtp-lowpri_destination_rate_delay = 2s
+smtp-lowpri_destination_rate_delay = 20s
+smtp-lowpri_destination_concurrency_failed_cohort_limit = 100
+
 
 # SSL configuration (outbound).
 smtp_tls_CApath = /etc/ssl/certs/