diff --git a/testsite/group_vars/xmpp.yml b/testsite/group_vars/xmpp.yml
index 4229ecdf74b170996b8cd194482ac85d1a3aa3e9..8edc393bdefb0608424f8711b2eb715606652043 100644
--- a/testsite/group_vars/xmpp.yml
+++ b/testsite/group_vars/xmpp.yml
@@ -5,7 +5,7 @@ local_mail_aliases:
 
 smtp_relay_host: mail.{{ testsite_domain }}
 
-smtp_relay_truststore: /etc/ssl/certs/ca.pem
+smtp_relay_truststore: "{{ lookup('file', inventory_dir + '/tls/ca.pem') }}"
 
 xmpp_administrators:
   - john.doe@{{ testsite_domain }}