diff --git a/roles/mail_forwarder/templates/main.cf.j2 b/roles/mail_forwarder/templates/main.cf.j2
index 3ac8ccdd36ba5a0d4a07a748c35a0edf121ad7a3..3b2ee72c8f991afc5be0fa1e453881da406798b9 100644
--- a/roles/mail_forwarder/templates/main.cf.j2
+++ b/roles/mail_forwarder/templates/main.cf.j2
@@ -24,7 +24,7 @@ smtpd_use_tls=yes
 smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
 smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
 smtp_tls_security_level=verify
-smtp_tls_CAfile=/etc/ssl/certs/smtp_relay_truststore
+smtp_tls_CAfile=/etc/ssl/certs/smtp_relay_truststore.pem
 
 # See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
 # information on enabling SSL in the smtp client.